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SCIENTIFIC AMERICAN
U MONTHLY
FORMERLY SCIENTIFIC AMERICAN SUPPLEMENT
■Stn(
hs*n!an
AUG 3 1920
Producing Flies with Horns
Artificial Siamese Twins
Microscopic Water Contaminators
Peace-Time Uses of the Gas Mask
New Method of Damascening Metals
Machine Made Laces and Embroideries
Eye Protection in Welding Operations
Steels for Automobile Parts Terminal Wastefulness at New York Increasing the Utility of the Tractor
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TABLE OF CONTENTS, JULY, 1920
Winged "Submarines" for High Altitude Flying 3
Recent Discoveries Regarding the Stars 1
Is the Earth Expanding or Contracting? 7
Microbes 2,000 Years Old 11
Surgical Use of Beef-Bone Screws 12
Dancing Birds 15
Producing Flies with Horns IS
Artificial Siamese Twins 19
Turtles, Terrapins and Tortoises 21
Microscopic Water Contaminators 2S
Theory and Practice of Lubrication 32
Peace-Time Uses of the Gas Mask 37
A New Cadmium Vapor Arc Lamp 40
A New Method of Damascening Metals 42
Catalysis by Means; of Precious Metals 45
Machine-Made Laces and Embroideries 47
Eye Protection in Welding Operations 52
Deep Etching of Steel ' 54
Steels for Automobile Parts 59
Terminal Wastefulness at New York 61
Increasing the Utility of the Tractor 66
More About High Flying 70
Departments
Science and National Progress 74
Fog and Smoke. The Use and Value of Physical and Chemical Constants.
Research Work of the United States Bureau of Standards. Calibration of Barographs Used in Airplane Altitude 'Measurements. Study of Power (Factor in Polyphase Systems. Comparative Tests of Normally and Finely Ground Cement. Refractory Crucibles. Investigation of Composition and Preparation of Sucrose-Invert Sugar Syrup.
80
Notes on Science in America S2
California Earthquakes During 1919. Effects of Anaes- thetics on Plants. The Planetesimal Hypothesis in Re- flation to the Earth. Research in the Psychology of Aviation.
Progress in the Field of Applied Chemistry 85
Industrial Fellowships. Problems in Wool Manufacture. Jelly. The Gas Mantle. Substitutes for Platinum. Cat- tle Food from Seaweed. Pearl Barley. Brass. Land Clearing and Chemistry. Leather in Engineering.
Progress in the Field of Electricity 88
Proposed 220,000-volt Transmission Line for California. Thermionic Valves. Safety Devices for the Safety Car. Use of Electricity in Metallurgical Processes. New Elec- tric Evaporating System.
Survey of Progress in Mechanical Engineering 91
Obturators Versus Piston Rings. The General Trend of Diesel Marine Machinery. Mechanical Screenless i Air Filters. Chantoaine Metallurgical Furnaces. Thrust Boring in Earth.
Progress in Mining and Metallurgy 94
Nature of Coal. Modern Commercial Explosives and ■ * Their Uses. A Reflecting Microscope for the Mining- Engineer. Efficiency of Use of Oil as Fuel.
Correspondence 96
The Origin of Volcanoes.
Shorter Items
Temperature, Means for Predicting Barometric changes. . 10
Lemons and Vitamines 14
Increasing Leaf Growth by Perforating the Root 14
The Courting Antics of the Fly 17
How Spring Flowers Can Bloom Unharmed in Spite of
Frosts 27
Voluntary Determination of Sex by Means of Chemicals.. 27
Pigments, of Flowering Plants 36
Protecting Mine Timbers from Fire 46
White Coal Available in Canada 65
A Fos Eliminator for Motion-Picture Studios 73
SCIENTIFIC AMERICAN MONTHLY
(Successor to Scientific American Supplement) Edited by A. Russell Bond
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Copyright, 1920, Scientific American Publishing Co.
PEACE-TIME USES OF THE (IAS MASK— TESTING >SUGAH TURKS WITH TOBACCO SMOKE (SEE PAGE i(7
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VOLUME II NUMBER 1
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WINGED ".SUBMARINES" FOR HIGH ALTITUDE FLYING.
Not content to dwell where Nature placed him, man has en- deavored to burrow into the waters of the ocean and to penetrate into the higher reaches of the ocean of the air. By means of (living "suits men have descended to a . maximum depth of some 300 feet, but even a dive of 100 feet would be a serious undertaking for the average man. In the ordi- nary diving suit the pressure of the surrounding water is im- parted to the air which the diver breathes, and, consequently, his lungs and his whole being are subjected to severe strains. The only method of descending into the ocean with any de- gree of comfort is to go down in a chamber in which the air is maintained at atmospheric pressure. This is possible in submarine vessels or in diving suits constructed of steel so as to resist the external pressure. However submarines so far built dare not descend to a depth of more than 200 feet ; for below that depth the crushing weight of the water is liable to strain them severely if it does not completely crumple them.
In aerial navigation we are going through the same course as was pursued in the development of submarine navigation. Hitherto flights to extreme altitudes have been of the nature of aerial dives or brief excursions and the pilots who essayed these perilous expeditions have been equipped with oxygen breathing apparatus or oxygen masks which correspond to diving helmets. Fortunately the difference between air pres- sure at sea level and that at an altitude of five or six miles while considerable is in no way comparable with that of de- scending 300 feet into the depths of the ocean. Nevertheless even with aerial diving helmets we are unable to rise much above an altitude of six miles. It is true that the altitude record is 36,020 feet, made by Major Schroeder a few months ago, but there are only two others who have ever reached an altitude of more than 35,000 feet and even 30,000 feet has been reached by very few aviators.
A recent development consists in employing a special re- lease valve automatically controlled by barometric pressure so that it will feed oxygen to the mask worn by the aviator in proportion as he requires it. However, even with such apparatus it is a question whether it could be possible for an aviator to rise to an altitude of, say, 40,000 feet. Labo- ratory experiments indicate that at a pressure corresponding to that height, the tension of the oxygen in the lungs falls so low that the tissues are unable to make use of it. Strange to say a certain amount of carbon dioxide is needed, not merely to dilute the oxygen but' to increase the pressure of oxygen in the blood. Just how the carbon dioxide functions has not yet been determined, but it seems to be needed to aid the lungs in absorbing the required oxygen in rarefied atmos-
pheres. Experiments have therefore been made with oxygen, in winch a certain proportion of carbon dioxide has been mixed. However, even with this improvement, it is hardly likely that flights of extreme altitude will become very popular. Only hardy passengers, men with strong constitutions, would be able to take such flights. At best passengers would find the wearing of masks or "aerial diving suits" a decided nuisance.
It is not for the mere purpose of satisfying human ambi- tions that aerial navigators have tried to rise to high levels, nor is it with the purpose of exploring the upper strata of the atmosphere. Such explorations can be and are carried on successfully by means of sounding balloons equipped with instruments that record automatically the meteorological con- ditions encountered. There are material advantages to aerial navigation in rising to high altitudes. Head resistance is greatly reduced and much higher speeds are therefore obtaina- ble ; hence high flying is economical in time and fuel. Further- more, there are prevailing winds at various altitudes which could be utilized by the aeronaut or aviator were he able to guide his machine at will to a level at which there was a current of air blowing in the direction of his course.
If diving suits fail us why not use "aerial submarines," that is, enclosed cars in which air at atmospheric pressure can be maintained?
By this means alone would it be possible for the average passenger to endure and enjoy sustained flight in an extremely rare atmosphere. He would be relieved of all the perils of high altitude conditions and would not experience the slightest discomfort.
This interesting subject was discussed in an article pub- lished in the January issue of this journal. On page 70 of the present number, there is an article by Dr. Guglielminetti which gives further information on the subject. He points out the advantages of this method of navigation in a rarefied atmosphere. The air pressure requisite even at ex- tremely high altitudes would not be much greater within the car than in the atmosphere outside and a very strong con- struction for the car would not be necessary. Special oxygen tanks would not be required, as it would merely be necessary to pump into the car with a blower enough air to keep the pressure at the normal of sea level. A biplane has been de- signed with an enclosed car capable of carrying a large num- ber of passengers. Special interest attaches to the chart which shows the range of travel of this aerial bus and its load capacity for various distances along lanes of travel running up to six miles above the earth.
It is more than probable that we shall soon see the "winged submarine" in service making long distant flights in remarkably fast time.
Recent Discoveries Regarding the Stars
The Motion, Brightness, Distance and Distribution of Stars and Spiral Nebulas
By John Candee Dean
SUMMER days draw us to outdoor life, and we find mild evenings very agreeable for star gazing, on clear moon- less nights. As we stand under the great dome of the heavens, in whatever direction we turn, we see the light of far distant stars shining down upon us.
The ancient belief was that the stars were all about the same distance from the earth. They were thought to be fixed in the "crystalline heavens," a huge, hollow crystal sphere, with the earth at its center. The earth was supposed to be stationary, and the crystal sphere rotated once every twenty- four hours. We now know that the distances of different stars vary enormously.
Naked eye observations of the constellations indicate that the fixed stars have not changed their relative positions since the days of Homer. There has, of course, been a shift- ing of the sphere of the heavens due to precession, but with relation to the Milky Way, the constellations appear not to have changed in 2,500 years. When, however, they are ex- amined with the telescope, it is found that the stars are mov- ing at great velocities in various directions.
STELLAR MOVEAIENTS
The astronomer Kapteyn found that the average speed of stars is about 23 miles a second or seven billion miles a year. There are some high speed stars with velocities of 100 to 150 miles a second. These high velocities show that their motions are nearly in straight lines and practically independent of their mutual attractions. In spite of the speed of these "runaway stars," it would require nearly 200 years for the nearest of them to move a distance equal to the moon's appar- ent diameter. They are too small, however, to be seen with the unaided eye.
The motion of stars in the line of sight, that is, to or from us, is called radial motion, while motion at right angles to this, or across the sky, is called proper motion. The radial motion, or motion in line of sight, is determined by spectro- scopic observations. If its distance is increasing, its lines in the spectroscope are shifted toward the red, and if the star is moving toward us its lines are shifted toward the blue, this motion is easily translated into miles. The proper motion of a star cannot be determined in miles unless its distance is known.
The theoretical fundamental of space is the ether which is frictionless, elastic, immovable, continuous and pervades all space. It is the medium which carries light. Light is not a substance, but is a wave motion of the ether. Several attempts have been made to determine the motion of the sun with respect to the ether, which is supposed to be stationary, but such attempts have failed. The sun with the whole solar system is moving in the general direction of the star Yega in the constellation of the Lyre. This point which is found to lie five or six degrees from Vega is called the apex of the solar motion. ■ The antapex is in the general direction of the star Sirius. That is, we are moving toward Yega and away from Sirius at a velocity of about 12 miles a second.
Interstellar space is estimated to be at a temperature of about 500 degrees below freezing. At a distance of 200 miles from the earth's surface this low temperature prevails. The absolute limit of cold is 523 degrees Fahrenheit, below the freezing point. This is called the absolute zero. Artificial cold within two degrees of this temperature has been pro- duced in the laboratory. There is no air in space and the vacuum is nearly perfect. It is probably a more nearly per- fect vacuum than can be obtained artificially, consequently the stars and planets move through space without friction.
It must not, however, be assumed that there is no matter in space. The cosmic matter in space is so thinly diffused that it has practically no effect on light. It has been shown that less than 1 per cent of starlight is absorbed by traveling for thousands of years through space.
Moulton tells us that the large velocities of stars show that their motions are nearly rectilineal and practically indepen- dent of their mutual attractions, except when two or more pass near each other. It can easily be shown by the principles of celestial mechanics that mutual gravitational attraction of the stars cannot generate such enormous velocities. "There is no reason for assuming that the stars were originally at rest, and hence we are under no obligations to account for their motion any more than we are for their existence."
The nearest star visible to the unaided eye, in our latitude, is the Dog Star, Sirius. It is also by far the most brilliant of the millions of fixed stars of our universe. As we gaze at it we note other smaller stars near by. We call them smaller because they look small, but this is on account of their vastly greater distance from us. A star that shines with a faint light may be dimmed by distance and in absolute brilliancy may be many times brighter than the Dog Star.
EXTENT OF THE MILKY WAY
The Dog Star is in the western edge of the Milky Way. a great belt of stars that encircles the earth. When a photo- graphic plate is exposed, in the telescope, to the light of the Milky Way it is found to be packed with thousands of stars. The Milky Way is the very foundation of our stellar universe. It has been found that many of its stars belong to two great streams flowing in opposite directions which interpenetrate each other without interfering with their movements. Milton says :
The Galaxy, that Milky Way
Which nightly as a circling zone thou seest
Powdered -with stars,
A broad and ample road, whose dust is gold.
It is impossible to express, in adequate language, the im- mensity of the Milky Way. It fills our minds with indescrib- able grandeur. This stupendous girdle is composed of millions of vast suns whose depths are beyond the reach of our largest telescopes. All visible stars belong to this great galaxy of stars. Its shape is supposed to be like a watch case. When we look at the Milky Way we are gazing through the longer diameter of the case which gives an impression of stars closely packed together, and when we look away at right angles to the Milky Way, we are looking through the shorter diameter of the case, and the stars appear scattered.
From what has been said, it will be seen that the Milky Way is a huge cluster to which our solar system belongs. It is found to be enormously larger than astronomers had pre- viously supposed.
STELLAR DISTANCES
Stellar distances are measured in light years. The pro- gressive velocity of light is so great that we cannot form any' mental conception of it. Light of all colors travels at the same velocity. It would pass around the earth about 450 times a minute, its speed is six trillion miles a year, and yet it may take as much as 200,000 years for light to pas- through the limits of the greater diameter of the Milky Way. Among the objects of the stellar universe are globular clus- ters of stars. The total number of known globular clusters is sixty-nine. They belong to the general system of the Milky Way, but are not in the Milky Way. They are at remote dis- tances from us varying from 1S.000 light years to 300,000
July, 1920
SCIENTIFIC AMERICAN MONTHLY
g
light years. The host known globular cluster is that in the constellation of Hercules. It is just visible to the naked eye, but in a telescope of even moderate size is a splendid object, sparkling like a cluster of small diamonds. Its distance is esti- mated by Shapley at about 35,000 light years.
STUDY OF GLOBULAR CLUSTERS
Within a few years our knowledge of the structure and extent of the stellar universe has been greatly extended, largely through the study of globular star clusters by Dr.
FIG. 1.
SPECIAL XKiBULAS IN A REGION SOME DISTANCE FROM THE MILKY WAY
There are 53 rings : at the center of each there is a nebula. Space covered is about equal to that of the full moon.
Such bright stars as Canopus; Beteiguex, Deneb and lieta Centauri are so far away as to be practically without sensible parallaxes. Recently photography has been successfully ap- plied to this problem with increased accuracy in the results Of estimating stellar distances.
A still more recent and very promising method of finding the distance of stars has arisen from spectroscopic methods of predicting stellar magnitudes. This method is based on the discovery that the "ultimate magnitude" of stars can be found with surprising accuracy from the relative intensity of certain lines in their spectra. Knowing the ultimate mag- nitude and the relative brightness, their distances can be de- termined by comparison, with nearer stars whose distances have been found by their parallaxes. Comparison of dis- tances computed by this method with the distances computed by parallactic methods are said to agree very closely. This remarkable discovery may in time enable astronomers to measure the visible depths of the universe. At present the weakness of the spectra of faint stars limits its application to the brighter ones.
It has been shown by the Harvard classification of stars that the older stars are the coolest and are also the swiftest in their movements. The fact is, that the entire universe down to the smallest atoms is in intense motion. From this it has been suggested that all matter is alive. That is, life is a property of matter. A wealth of evidence has been col- lected which proves that the atom is an organized planetary system of dazzling complexity in which electrons simulate the movement of the planets in our solar system. The nega-
Shapley, of the Mount Wilson Observatory. He has discovered, by the study of certain stars which vary in brightness in the short period of one day, that they are about 100 times as bright as the sun. These short period Cepheid variable stars are found in the globular clusters and they are ingeniously used to tell the story of the distances of the clusters them- selves. Those stars whose period of variation is four days are found to be 400 times as bright as the sun. Knowing their apparent brightness, and also knowing their real bright- ness, Shapley is able to compute their distance, and thus de- termine the distance of the star clusters. These distances are astounding. The great Hercules cluster previously re- ferred to is 35,000 light years away and the remotest cluster observed is computed to be 220,000 light years away.
Our sun belongs to the fixed stars, and being near us, affords an opportunity by comparison, to determine the structure of distant stars. They are all gaseous bodies, and the spectro- scope demonstrates that they are composed of the same ele- ments as the sun. The sun is classed as a "G" star and is, therefore, below the average in temperature. In regard to size, it is also moderate. The Dog Star is estimated to be forty-eight times as bright as the sun. If we were as near to that star as we are to the sun, we would be burned to a crisp by the intense heat. The brilliant star Spica is 13,000 times as bright as the sun, while Canopus, a very bright star in the south polar sky, is 55,000 times as bright as the sun. Spica and Conopus are both about 500 light years from us. To express their distance in miles, write down three and add fifteen ciphers.
FIG. 2. A TYFICAL SPIRAL NEBULA— MESSIER 51
MEASUREMENT OF DISTANCES
The distance of a star is determined by its annual parallax. The operation of measuring a star's parallax is considered the most difficult in the whole range of practical astronomy. No star has yet been found with a parallax as large as one second of a degree, and this large parallax is a microscopic distance on the circle of the telescope. The triangle would be equivalent to one with base of three inches and sides 60 miles long. Only a few of the very nearest stars have sensible parallaxes, therefore, we know the accurate distance of but few stars.
tive electrons of the atom revolve around their positive nuclei, like planets around the sun. The planet Neptune requires 165 years for a single revolution around the sun, while the electrons of atoms complete their revolutions around their nucleus in the millionth or the billionth of a second. These electrons are thought to revolve in a series of concentric orbits, all in the same plane. If oxygen gas, at atmospheric pressure, could be magnified until each nucleus were equal to the mass of the sun, we would have the sidereal universe reproduced in which the mean distance between the atoms would approximate the mean distances between the fixed
6
SCIENTIFIC AMERICAN MONTHLY
July, 1920
stars. Thus in oxygen gas and other gases the sidereal uni- verse is reproduced in miniature.
Since the forces acting in the atom are found to be elec- trical, may not the force acting in the stellar universe be electrical? Is not the force of universal gravitation electrical? Should not the universality of stars lead us to infer that the force of universal gravitation is an electromagnetic force?
FIG.
3. SUPPOSED STRUCTURE OF THE UNIVERSE ACCORDING TO WILLIAM HERSCHEL
There are but two classes of objects seen in the distant heavens : stars and nebulas. The nebulas are divided into three classes, irregular, planetary and spiral. There are certain nebulous stars called the Wolf-Eayet stars. It is also thought that various black patches in the sky are caused by dark irregular nebulas. Only two bright nebulas are visible to the unaided eye, viz.: the great irregular nebula of Orion and the great spiral nebula of Andromeda. It is related that a sea captain in crossing the ocean discovered what he thought to be a comet, which he watched with in- terest during his voyage. On arrival at the port of Boston, he hurried to the Harvard Observatory to announce his discovery, but was there informed that he had been looking at the nebula of Andromeda.
This most beautiful spiral nebula appeal's to the naked eye as a hazy patch of light, and it requires a large telescope to bring out its beauty. With the three-foot Crossley telescope at the Lick Observatory several fine photographs of this neb- ula have been obtained. On a plate exposed in the Crossley reflector covering a portion of the sky, some distance from the Milky Way, in a space but little larger than that of the full moon, no less than 53 spiral nebulas are shown. A count of the small spirals on photographic plates, taken with the Crossley reflecting telescope at the Lick Observatory, indi- cates that in the whole heavens there are at least 700,000 of these small nebulas within reach of very large telescopes. No doubt, the 100-inch telescope at the Mt. Wilson Observatory will be able to show more than a million.
The spirals are never found in the Milky Way, they in- crease in numbers as the poles of the Milky Way are ap- proached. Their speed of movement is higher than any other objects in the heavens, sometimes averaging several hundreds of miles a second. They generally have but two prominent arms winding out from their central nucleus. The latest and most sublime theory regarding them is that they are distant universes of stars. Prof. H. D. Curtis of the Lick Observatory says :
"On this theory could we be transported out into space a distance of hundreds of thousands or millions of light-years, to where the spirals are, and look back from that point at our own particular Milky Way, and stellar universe, it would perhaps appear to us as a spiral nebula."
On the theory that the spirals are separate Milky Ways, or "island universes," Curtis estimates their distance from us at
from ten million to one hundred million light-years. He says, "It is certainly a wonderful, a brain-staggering conception, more tremendous even than any other of the mighty ideas of astronomy, that our own stellar universe may be but one of hundreds of thousands of similar universes."
The illustration Fig. 1 is from a photograph covering an area of the sky about equal to the apparent size of the full moon. The nebulas are at such vast distances that they are mere specks shown at the centers of the circles. There are 53 nebulas in this small area. Fig. 2 shows the spiral nebula called Messier 51. It is of a typical form with two arms leading out from the central nucleus and winding around it. Fig. 3 is from a drawing by Sir William Herschel made the latter part of the eighteenth century. At the center A is the star cluster of our galaxy, or our universe of stars ; beyond and around it are numerous exterior universes of stars. It is remarkable that in Herschel's time these distant, so-called nebulas could not be seen and their existence was purely a matter of theory. Now through the use of our larger tele- scopes it is found that there is visible evidence to support the Herschelian hypothesis.
While the sun moves at a uniform rate and probably in a straight line the earth, owing to its motion around the sun, describes a huge spiral in space. Because the plane of the earth's revolution is inclined to the line of the sun's way, a variable motion of the earth toward the apex is produced. Referring to Fig. 4 the earth's motion toward the sun's apex is shown to be seven times as rapid at b as at d. At b the velocity is 21 miles a second, while at d it is only 3 miles a second. Fig. 4 shows the course of the sun and the earth
FIG. 4. MOVEMENTS OF
EARTH AND SI'X TOWARD
APEX OF THE SUN'S WAY
DURING A PERIOD OF
ONE YEAR
FIG. 5. THE SPIRAL
COURSE DESCRIBED BY
THE EARTH DURING A
PERIOD OF EIGHTEEN
MONTHS
during a period of one year. The first three months the sun moves from e to b, and the earth from a to b. The second three months the sun moves from b to f and the earth from b to c. The third quarter the sun moves from f to d and the earth from c to d. The last quarter the sun moves from d to g and the earth moves from d to h. Fig. 5 is another view showing the helical course through which the earth actually moves during a period of eighteen months.
Is the Earth Expanding or Contracting?*
Theory of a Gaseous Core Denser than the Solids Which Form Out of It and Incase It
By Hiram W. Hixon
I In the Scientific Amebican Monthly for April, pages 292 to 297 there appeared an article by Entile Bclot, Chief Engi- neer of Manufactures under the French Government entitled "The Ballistics of Volcanoes" in which the marine theory of the origin of volcanoes is defended. The author of the present article does not accept M. BMot's arguments but holds to the theory that they arc the result of a gradually shrinking planet. . I letter by Mr. Hixon coinni<enting on M. Helot's article will be found on page 9(3. — Editor, j
THE cause of elevation, folding, faulting and other changes in the earth's crust which raised what was once covered by the sea, in a former geological period to the land we live on, has been variously stated, but further examination has shown that the old hypothesis will not ex- plain the observed facts.
It is not generally known what the cause of causes is, but if the argument which follows is correct then it must be local and regional reduction of density which causes elevation and local and regional increase of density which causes subsidence. Unloading or erosion accentuates elevation, and loading by deposition of sediments accentuates depression, but neither is the ultimate cause of either elevation or depression. The Grand Canyon area was a region of depression for a long geological period, and then it became a region of elevation. The unconformities show (Fig. 3) that these conditions have been reversed three or more times on a gigantic scale, and many times on a minor scale. In Dutton's "Monograph on the Tertiary History of the Grand Canyon" his analysis of the process by which the Canyon was cut is that the river was there first, and the plateau rose in the path of the river. This is obviously true, because rivers do not run over plateaus 8,000 feet high and cut canyons through them, when there are regions of less elevation in which they can flow. We are therefore confronted with the necessity of finding a competent cause for the elevation from below sea level to an altitude of 18,000 feet above sea level, of a dome in the earth's crust 150 miles in diameter. There have been removed from the Grand Canyon area, according to Dutton, 10,000 feet of strata
Stretch Compression
FIG. 1. NORMAL FAULT FIG. 2. REVERSED FAULT
The normal fault is called normal because it is the dominant type, and it is impossible to produce this type by contraction of the hot interior of the earth acting on the cold crust, for slumping down must be preceded by elevation.
of various geological ages overlying the carboniferous, which is exposed in the rim of the Canyon at present at an altitude of 8,000 feet in the north wall. Loading furthered depres- sion, of the sedimentary series, but when deposition ceased, the surface was still at or below sea level, and erosion could therefore not be the cause of elevation. The elevation is greatest where erosion has gone deepest, which is in the Canyon itself. vThe proof of this is that all the surface drainage is away from the Canyon rim and one is obliged to go up hill to the Canyon. This is due to the fact that the removal of the immense weight of material in the cutting of the Canyon has caused an increased uplift over the area near the Canyon and reversed the dip of the strata as in an anticlinal.
♦Reprinted from Popular Astronomy, Vol. XXVIII, No. 5, May, 1920.
But the elevation has been great in regions remote from the Canyon, so that the cutting of the Canyon cannot be the cause of more than local adjustment to anisostatic balance. This isostatic balance is world wide as well as local, and the con- tinents and islands which stand above the ocean bottom do so simply because the sub-crustal material beneath them is less dense than beneath the more depressed parts of the earth. The rocks composing the stratified series in these elevated regions testify to the fact that they were deposited below sea level, and we are, as in the case of the Grand Canyon area, obliged to explain how the immense weight of the con- tinental masses have been lifted to their present positions.
The contraction hypothesis is incompetent to explain these changes of altitude because of lack of strength in the crust, as shown by Woodward and other investigators. Calcula- tions were made on the strength of earth domes, taking into consideration strength of materials and weight, and it was found that when considered as a dome of the radius of the earth, twenty-five miles thick, and of material equal to the crushing strength of granite, that such domes would not sup-
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s
Archaean River level Algonkian
FIG. 3. DIAGRAMMATIC ELEVATION OF THE NORTH WALL OF THE GRAND CANYON OPPOSITE BRIGHT ANGEL TRAIL Two great unconformities, each of which marks a period of erosioni of a land surface subsequently submerged and deeply covered with sediments. The region was later elevated and a dome or mountain range eroded off, and this repeated three times.
port one five-hundredth part of their own weight if they were one hundred miles in diameter. Obviously, if domes of such small diameter are not self-supporting, then domes of conti- nental size cannot be, and the crust must at all times be sup- ported by the material below it.
If it is in isostatic balance at all times, and varies in alti- tude from one geological age to another, then the only solu- tion of the problem is that a part of the subcrustal material varies in density between these dates.
The cause of the variation in density is now the chief con- cern, and it is necessary to depart a considerable distance both in time and subject to explain that.
To begin with, it is necessary to define several things :
1st — Critical temperature is the temperature above which matter is always in a gaseous condition regardless of pressure.
2nd — Gas is matter above its critical temperature.
3rd — The sun is above its critical temperature as a whole and therefore gaseous throughout, and in the central portion gravitational compression makes gases of a greater density than, the solids that may form out of them when cold.
4th — Gas of greater density than solids is still gas, and subject to the laws governing diffusion, and will support or float a crust of solids and may be called solid gas.
5th — According to Graham's law of the diffusion of gases in a mixed body of gases, each gas occupies the whole space as if the other gases were absent.
6th — In a sun or planet in an incandescent condition it must follow, if these laws be true, that each gas will diffuse clear through the whole planet irrespective of density, and occupy the space where gravitational compression has made the density greater than the solids which will form out of them at the sur- face when cold.
SCIENTIFIC AMERICAN MONTHLY
Jt-LY, 1920
7th — Rigidity is a property of matter that resists deforma- tion to sudden movement and is relative to that movement.
For example, the earth as a whole is said to be as rigid to the tidal movement as a sphere of steel, but it yields to centrifugal force, and is of greater equatorial than polar diameter. It also yields to reduction of density as shown, and the isostatic balance is preserved by yielding to small forces long continued, like loading and erosion.
Rigidity is a property of cold matter, as we are used to it, that is lost when the temperature is much increased whether fluidity is reached or not, as for example : A bar of steel heated in a forge is rigid on the cold end and soft on the hot end.
Therefore, an increase of temperature of 1 degree Centi-
Mountain uplift
Volcano
-- Solid crust
FIG. 4. DIAGRAMMATIC SECTION OF THE EARTH TO IL- LUSTRATE THE THEORY OF A GASEOUS CORE DENSER THAN THE SOLIDS WHICH FORM OUT OF IT
The core contains some of each of gases which were originally in, the gaseous planet sun, and are held there by the power of diffusion until liberated toy the cooling of some of the elements below their critical temperatures. These elements become solids because the gravitational compression raises the fusion point to the critical temperature. The average density of the earth is about 5.6, water being 1 ; so that at the center the density must reach 10 or more. At the surface the cold material has an average density of 2.7, and pressure increases at about 3 tons per square inch per mile of depth. The rate of increase, increases with the depth and at the center of the earth is a'bout 25,000 tons per square inch. The crust is much thinner in regions of volcanic activity and the increase of temperature with depth is much more rapid than in regions covered with thick beds of sedimentary rocks. The average, so far as known, is about 1°'C. for 100 feet of depth, or about 50°C. per mile of depth, which would give 5,000 "C at 100 miles if the increase were uniform, which it probably is not. If 5,000°C. is reached at 100 or 150 miles of depth that would be high enough to volatilize all known substances.
grade for each 100 feet of depth will cause a plastic condition or a zone of rock flowage long before the melting tempera- ture is reached in a solid globe.
The most recent information regarding increase of tempera- ture with depth has been obtained from a well drilled to a depth of 7,580 feet at Valley Falls, W. Va. The temperature near the top of the hole was 52° and at the bottom 170° F. This increase is at the rate of 1.568F. or .865°C. per 100 feet, and is also the greatest depth to which a bore hole has been drilled.
As a result of rock flowage without melting, all cavities are closed at a mile or less of depth, and in deep mines it has been found that surface waters do not go much below two thousand feet, and below that the workings are dry. Notwith- standing this fact, lavas which come from great depth are porous and full of gas and steam when they issue from the craters, and it is now known that gases, a considerable por- tion of which is steam, 75 per cent by analysis in the report of the observatory on Kilauea for July, 1919, are the sole cause of the elevation of the lava in the craters and the craters themselves, and all the other phenomena known as volcanic action, and as I shall show, also of geysers and hot springs.
Chamberlain's postulate of a cold earth developed from planetesimals is not in accord with the observed fact that the
moon, with only one-eighty-first part of the mass of the earth was formerly molten, as shown by the crater rings which are visible on its surface.
Assuming an incandescent condition for the earth before it had a crust, we have the origin of the gaseous core or solid gas, with rigidity corresponding to compression and containing some of each of the gases which were in the original gaseous planet.
The gases of low critical temperature will continue to be held in the gaseous core by the power of diffusion so long as the temperature is above the critical point for all, and as the mass on the outer surface of the gaseous core loses heat and falls below the critical temperature of some of the ele- ments, they pass from the gaseous to the solid condition be- cause the gravitational compression has raised the fusing point to that of the critical temperature, eliminating the fluid condition. The gases of low critical temperature such as Nitrogen, Hydrogen, Co, Co2, So2, etc., can no longer remain in diffusion with solids, and they work their way up through the zone of solid flowage to the bottom of the zone of fracture by some process similar to osmosis ; by which they constitute an integral part of a non-porous medium with additions from below and relief from above. They act as carriers of heat from the zone of critical temperature to the focus of volcanic fusion, and when sufficient gases and heat have accumulated break through to the surface and cause the various physical phenomena known under the head of volcanic action (Fig. i).
They rise uniformly from the zone of critical temperature or solid gas, but owing to long established channels do not reach the surface except in localities of volcanic activity. Their first effect is to reduce the density of the rock matter, which they fuse by their contained heat, and this reduction of density causes elevation at the surface of the solid crust in the same manner that the leavening gases cause the eleva- tion of the surface of a loaf of bread : Example, the Black Hills, S. D. When sufficiently accumulated, the elastic pres- sure of the gases pulls the zone of fracture apart, and the gases rush into the fracture carrying along the fused rock
Main range
FIG. 5. RESULT OF THE CREEP OF MATTER OF REDUCED
DENSITY BENEATH THE ZONE OF FRACTURE ON STEEP
SLOPES FROM DEEP SEA TROUGHS TOWARD
HIGH MOUNTAINS
The sea trough is deepened while the sea beaches and mountains
are elevated periodically at time of sudden movements and earthquake.
The submarine ridge to the left of the trough will m time become a
third range of mountains and the elevated trough will be filled
with the wastage of the mountains in the same manner as the
plateau surrounding Lake Titieaca has been filled. The festoon of
parallel ranges of mountains shown on maps are thought to have
been formed in this manner.
matter as a dyke or sill, which may or may not reach the surface and result in volcanic action. Dissected craters are shown to be located above dykes, as witness the one on the Canyon rim at Vulcan's Throne, Grand Canyon (Dutton). Lavas are local fusions of rock by volcanic gases and vary widely in composition from the same crater at different erup- tions.
.In. v. 1920
SCIENTIFIC AMERICAN MONTHLY
The matter of reduced density below the zone of fracture tends to seek a higher level and displace matter of greater density. This results in the phenomenon known as stoping or thinning of the zone of fracture, and is characteristic of volcanic regions, and is the means by which craters are bored through horizontal bedded strata not otherwise disturbed, as for example, the diamond pipes in South Africa and Devil's Tower in South Dakota. This creep of rock matter saturated with gas from regions of great depth is influenced by the heat gradient or isogeotherms ; and in a region where deep ocean areas border on the land, and high mountains are near the sea, it results in sudden upward movements which carry the crust blocks in a sudden lurch, just like a land slide only reversed in direction. In this way the ocean becomes deeper and the hind higher (Fig. 5). The crust blocks moved in this maner may contain many thousand cubic miles of matter, and the momentum of such a mass when suddenly stopped is enough to shake the whole earth, and the result is called a tectonic earthquake. The volcanic type of earthquake has the same cause of causes but is more local in character. Being at a shallower depth, its effects are not felt over so great an area and may result from the intrusion of steam accompanying the advance of a dyke or sill into a fault plane which was opened by the elastic pressure of the steam, and the shock may be partly due to the sudden condensation of the steam when in contact with the cold wails.
Such a fault plane opened and closed several times with accompanying noises of rushing steam and heaving of the ground, will explain most earthquakes. The condensed steam escapes as water along with the gases through craterlets, many of which were found at Charleston and New Madrid.
The accumulation of matter of reduced density beneath a mountain range which has been shown to exist by the use of a vibrating pendulum according to the Coast and Geodetic Survey, is to be accounted for in the manner just described. And as the accumulation takes place from the opposite sides of the range of mountains, and the crust blocks are carried in two opposite directions, folding and overthrust occur as a result without the contraction of the planet as a whole, the stretch of normal faults compensating the folding and re- versed faults (Figs. 1, 2 and 6). It has been estimated that all the contraction produced by the loss of heat in a hundred million year period would not result in decreasing the circum- ference of a great circle of the earth more than seven miles. It has also been estimated that if all the folding and over- thrust were ironed out of the mountain ranges in a similar great circle, that it would amount to one hundred and twenty to one hundred and fifty miles ( Chamberlain ) . Here is a dis- crepancy that calls for just the explanation offered : that fold-
Matter of reduced density. Probably granitic due to deposition of silica from hot solutions and formation of feld spar and mica under like conditions according to Le Conte and Sorby.
FIG. C. FOLDING AND ELEVATION OF A MOUNTAIN RANGE BY THE CREEP OF MATTER OF REDUCED DENSITY BE- NEATH THE COLD CRUST TOWARD THE AXIS OF ELEVATION OR CENTER OF A DOME.
The bottom strata are much more folded and crumpled than the top. because of their higher temperature and greater friction. The crust is carried in two opposite directions, and folding and over- thrust in The mountains is compensated for on the sides where the crust is stretched and normal faulted.
ing is due to the carrying of the crust against itself from the opposite sides of the axis of accumulation (Fig. 6).
Contraction is inadequate to account for the observed fold- ing and if due to folding would be continuous, whereas moun- tain building is epochal. According to the explanation given,
there may not only be no contraction, but actual expansion of the earth as a whole. The reason for this is plain. If the earth has a gaseous core denser than the solids that will form out of its gases, and its core by loss of heat is gradually be- coming solid, then it will occupy more space (Fig. S), and the earth as a whole will be expanding instead of contracting, which will mean a slowing down of its speed of rotation and a lengthening day. The reason for this is that the momentum of rotation is fixed and if the diameter increases by expansion
INDlAti
OCEAN
FIG.
AREAS OF SUBSIDENCE IN EQUATORIAL AND SOUTHERN AFRICA
the speed of rotation must decrease. The question is at once suggested, "Have we any evidence that it is expanding?" And the answer is supplied by the millions of normal faults, all of which indicate a stretching of the crust (Fig. 1), and also by the great rift valley which extends from south of the equator in East Africa to the valley of the Jordan in Palestine.
By analogy, the so-called Canals of Mars may be the result of the expansion of a once gaseous core on a rigid crust (Fig. 8), with the consequent inflow of most of the water on the surface and the growth of vegetation adjacent to the water. Also the slower revolution of the planet would explain whyr the inner satellite of Mars revolves in less time than Mars itself does, because the speed of rotation of the satellite would not be influenced by the expansion of the planet.
The point of greatest practical interest to students of this subject is the thought, that if all the land areas are held above the level of the ocean by reduction of density, then we and all air-breathing animals owe our development and ex- istence to that one fact, for without that force all the litho- sphere would have remained at a uniform altitude, and the waters of the ocean would cover the entire surface of the planet, and nothing living could develop, except it swam in the limitless sea.
Whether we have elevation or subsidence in a region is a relative matter, and depends on whether accumulation of the leavening gases in the regions below the zone of fracture is more or less rapid than their escape to the surface through volcanic vents, hot springs, etc., or the movement of matter of reduced density from beneath one region to another. The solution of the geyser and hot spring problem is simply a
10
SCIENTIFIC AMERICAN MONTHLY
July, 1920
calculation of the heat units that would have to be derived from the contact of cold surface water with hot rocks. In the Yellowstone Park there are reported to be about 4,000 hot springs, geysers and steam vents. Some of these dis- charge steadily a large amount of boiling water, while many are relatively small. All told, 20,000 gallons per minute does not appear to cover the quantity, and at 8 pounds per gallon, this would be 160,000 pounds- per minute, or 80 tons. Water has a specific heat of 1 and ordinary lava of 0.20, so that it would require the cooling of 5 times the tonnage of lava through the same range of temperature as the water, say 150°, from 62°F. to 212°F., or the same tonnage of lava cooled through five times the range of temperature, or 750° to supply the heat units.
There are 1,440 minutes in a day and 525,600 minutes in a year, which multiplied by 80 tons gives 42,048,000 tons of lava cooled through 750°F. to supply the heat for a single year. At 2.5 tons per cubic yard this represents about 16,800,- 000 cubic yards, or put another way, a cubic mile of lava would supply heat for 324 years, or 308 cubic miles would be required to supply heat for one hundred thousand years.
The geysers and hot springs are in deeply eroded country, young in a geological sense. Some of the geyser cones show signs of glaciation, so that they are evidently many times one hundred thousand years old. It is impossible that surface waters can come in contact with, or extract the heat from, such a huge quantity of lava by conduction, because the con- ductivity of lava is so low that if the outer surface be cold, though the interior be hot, relatively no heat would pass to the water.1
FIG. 8. EFFECT OF THE EXPANDING OF A GASEOUS CORE,
DENSER THAN THE SOLIDS THAT WOULD FORM OUT OF
IT, ON A COLD CRUST
The water would be ■withdrawn from the surface, and the speed of rotation reduced. The momentum of rotation must remain con- stant, and if the diameter is increased, the period of rotation must increase also. This is probably why the inner satellite of Mars revolves around Mars in less time than Mars revolves on its axis. The cracks in the crust would explain the so-called Canals of Mars, as well as the great rift valley of the earth in East Africa, and the rill cracks on the moon.
The travertine deposited from solution at the surface as a cone and all the way up the pipe completely isolates the pipe from surface waters as the casing of an oil well does, and therefore condensed steam from the gaseous core forming magmatic water is alone discharged.
The escape of all known gases from volcanic vents and from the fluid lava while cooling has been observed. This is in
aFor this reason any effort, to get power or steam from bore holes or shafts to great depth will end in failure, for after the waMs are once cooled the conductivity of the rock is too low to renew the heat readily. This applies to the article by Chas. Parson, F.R.S., in the May number of Scientific American Monthly.
accord with the known facts of what should be the case ac- cording to the law of diffusion of gases applied to a gaseous planet. Hydrocarbon gases have the same reason for being in the gaseous interior as the other gases, and their accumulation and condensation to oil beneath impervious sedimentary de- posits would explain the origin of petroleum.
The hydrothermal solutions resulting from the condensa- tion of steam from the interior would leach out the metals from the hot rocks in the path of their ascent, and deposit them in faults and fractures near the surface because of the effect of relief of pressure and falling temperature on the sol- vent power of the solution, thus making ore deposits.
Finally, the question of probability of the correctness of any hypothesis increases about as the sum of the squares of the number of observed facts that it will explain or agree with. If it will explain all of the known facts which other hypo- thesis explain and also those which they fail to explain it has an infinitely greater probability of being correct.
Sierra. Nevada
After Le Conte.
FIG. 9. THE BLOCK FAULTING IN THE GREAT BASIN IN
UTAH AND NEVADA ANOTHER EXAMPLE OF A REGION
SHOWING EXPANSION
The foregoing hypothesis explains all2 known geological phenomena except the rigidity of the earth to tidal distortion and that is assumed to be explained by gravitational com- pression of the gaseous core which produces rigidity as well as density greater than the solids which may form out of it. Even the hypothesis that the earth is solid is open to the same criticism because the high temperature would destroy the rigidity of a solid core.
TEMPERATURE AS A MEANS FOR PREDICTING BAROMETRIC CHANGES.
Aviation is giving increasing importance to weather pre- dictions and aviators must learn not only how to read weather maps but also how to interpret for themselves various local weather indications.
Two French scientists, G. Reboul and L. Dunoyer, have dis- covered a definite relation between the changes of temperature and those of barometric pressure.
It has been noted that a depression coming from the Atlantic is, in winter, always accompanied with a rise in tempera- ture, while the establishing of a high pressure system is accompanied by a fall of temperature. As variations in tem- perature usually precede those of the barometer, the former may be used to foretell the latter. Rising temperatures are favorable to a fall of the barometer; falling temperatures favor a rise. This fact may be easily verified by an exami- nation of isobar and isotherm maps. Hence the authors lay down the rules that (1) regions in which the temperature is rising are threatened with a fall of the barometer; and (2) regions in which the temperature is falling are threatened with a rise of the barometer. These rules apply with greater accuracy when the temperature on the land is below that on the ocean. As at present understood, they hold true only for latitudes above 45°, and in the months of winter.
Observations made in the regions of Central Europe during the six months from October to March, 1917-1918, afforded a basis for predictions which were fulfilled in from 64 to 76 per cent, of the cases recorded. — Compter Rendus, July 28, 1919.
"AM geological phenomena have their beginning in elevation, erosion and sedimentation, and elevation is shown to be due to reduction of density toy magnetic gases and is the first cause leading to all the others which are effects.
Microbes Two Thousand Years Old
Methuselahs of the Microscopic World Found in Papyrus of the Ptolomaic Era
Abstract of a Report to the French Academy of Sciences
IT would seem reasonable to suppose that in the more or less elaborate processes by means of which cellulose is trans- formed into paper in micro-organisms originally existing in the former would be destroyed. But thiss upposedly rea- sonable theory lias just been disproved in the experiments made by the French scientist, M. V. Galippe, a report of which was presented to the French Academy of Sciences on November 3rd, 1919, by M. Yves Delage.
M. Galippe declares that all sorts of paper contains in its fibers living organisms capable of being cultivated. He says:
"I have made use for many years of Alter paper sterilized in the auto-clave at a temperature of 120°C. for a period of half an hour. A direct examination of such sterilized filter paper by dilaceration (i.e., tearing asunder) and coloration shows that it contains within its framework and particu- larly in its fibers a large number of ovoid bacilli united in a mass. Those which we isolated were capable of movement. Several plantings of these were made with positive results.
"According to my observation the presence of living elements in filter paper (even sterilized) offers no great inconvenience, at any rate so far as rapid filtration of liquids is concerned, though it may be so in the case of organic liquids which filter slowly.
"It occurred to me to inquire what influence time might have upon such living creatures contained in paper. My researches extended to papers manufactured in the 18th century and even in the 15th century." M. Galippe continued his experi- ments as follows : "Fragments of paper were placed in con- tact with sterilized distilled water frequently stirred. These fragments were afterwards dried and allowed to remain for several hours in sterilized water which was supersaturated with ether. Then after having been dried again these frag- ments were planted with cultures. The 18th century paper thus treated was examined directly after dilaceration and coloration, and it was found that its fibers contained a certain number of ovoid bacilli. The cultures gave positive results the next day. Microscopic examination showed the- presence of numerous rods and of ovoid bacilli and diplobacilli as well as of microzymes and mitochrondial forms. The experimenter next treated paper from a book printed in 1496 in the same manner. In this case the direct examination of dilaceration and coloration revealed large micrococci containing a micro- zyme bacilli and numerous microzymes. The free micro- organisms in the preparation were capable of movement : those which colorized the fibers of the paper, on the contrary, remained immobile. Positive results were obtained from the sowings on the next day. Besides ovoid bacilli and rods the culture contained extremely curious mitochrondia forms recall- ing those previously observed by us in muscular tissue as well as in the epidermis of the petals of certain flowers. A num- ber of examinations of the same paper as well as new cultures made with it yielded some results. Furthermore, we found in one of our cultures a bacillus which was morphologic and iden- tical with the tetanus bacillus.
"Encouraged by these first results we were led to inquire whether paper still more ancient would give similar results, and thus through the kindness of a learned gentleman we were able to procure some fragments of Chinese MSS. It was not possible to assign the exact date of this but we were as- sured that they dated from a period long before the discovery of printing. The first of these two specimens (No. 1) seemed to be older than the second (No. 2) and was more resistant. After having been treated by the method indicated above these fragments of paper were examined with the following results :
"No. 1 contained in the interior of its fibers numerous ovoid
bacilli as well as rods, micrococci and diplococci. When sewn upon gelatine these fragments yielded positive results and the culture was found to contain rods, large ovoid bacilli and mitochondrial formations — all of these organisms were capable of movement. Two days after the culture was started we found within the fibers of the paper ovoid bacilli and chains (chainettes) and rods endowed with movement. These micro-organisms exhibited nothing peculiar in the process of their development.
"In specimen No. 2 the direct examination enabled us to perceive in the interior of the fiber ovoid bacilli of considerable volume. The culture made yielded positive results. These cultures contained mitochondria forms already referred to, as well as large rods, a great number of ovoid bacilli and like- wise many microzymes. After being incubated for three days, all these elements began to multiply and afterwards passed through a normal development. They were all capable of movement."
These very remarkable results fired M. Galippe's interest to such an extent that he determined to carry the question of the long life of these little Methuselahs still farther. From a well-known Egyptologist, M. Benedite, he succeeded in ob- taining fragments of papyrus belonging to the time of the Ptolemies, i.e., about 2,000 years before the Christian era. Upon bits of this papyrus were sown culture mediums. One of them was subjected to direct examination after being torn asunder and colored as usual. The large cells of the epider- mis remained united and were found to be unaltered. Some of these cells were empty, whereas others contained micro-organ- isms of various forms. Among these we distinguished large spherical bodies, rods arranged in chains, ovoid bacilli, micro- cocci, and diplococci. After three hours of hydration these intra-cellular micro-organisms, which had remained motion- less for so many centuries, all began to move. After the lapse of twenty-four hours cultures made with them exhibited signs that they were multiplying and developing — the mitochondria forms as well as the various micro-organisms observed in the direct examination.
These startling and unexpected results of the revival of life in organisms as dead apparently as Pharaoh's mummy induced the investigator to continue his researches, with a slight modi- fication of technique. Fragments of the aforesaid papyrus were macerated in pure ether to free them of the resinous matters contained which had rendered the observations somewhat difficult. When the fragments thus macerated were treated as before they exhibited the same results, except that the intra-cellular micro-organisms were found to be endowed with movement.
Finally the series of experiments was completed by making an anatomical and bacteriological examination of the plant from which the ancient papyrus was made — the Cyperus Papyrus. It is interesting to learn that when the epidermis of the stalk of this plant with all its leaf sheaths was examined some organisms were discovered that had been first found in the papyrus of the Ptolemaic era. In the cells of the fibers and in the cultures made therewith, similar mito- chrondria forms were found as well as ovoid bacilli, rods, and numerous microzymes, endowed with motion.
Previous researches made by M. Galippe, with the aid of Mine. G. Souflland have likewise established the high degree of resistance to the intra-cellular organisms to the action of heat and to various chemicals. Hence these microscopic living creatures, whose very existence was so long unsuspected, ap- pear to be really entitled to the name of minute Methuselahs.
11
Surgical Use of Beef-Bone Screws*
Their Advantages in the Repair of Fractures and in Bone Transplantation
By M. S. Henderson, M. D.
IN recent years, Bone grafting has become established in surgical practice as firmly as the more simple operation of skin grafting, and, as in the latter, it has been found that the autogenous graft is the best. Practically all failures can definitely be attributed to technical errors, such as too small a graft, infection, inadequate fixed bony approximation of the graft to fragments, and poor postoperative fixation of the part. I have found beef-bone screws to be a great aid in attaining this fixed approximation of the graft to the bone, and I believe that they would be employed more if their uses and methods of preparation were more generally known. I am well aware of the fact that a few surgeons have used them, but I present this article on their preparation and use be- lieving that it may be of interest to others.
There can be no doubt that, from a purely theoretical point of view, screws made from the bone of the patient, such as the bone pegs advocated by Albee, would be better than beef- bone screws. The theory when put into practice, however, has so many objections, such as the difficulty of making the screws or pegs properly, and the extra amount of bone used, that I have come to the conclusion that the beef-bone screws are to be preferred. The question of whether the beef bone is suitable for a graft does not enter into this discussion, for all that is demanded of the screws is that they provide fixation of the autogenous graft to the fragments. They are usually absorbed completely within from six months to a year.
We know that the bone transplant must be held firmly in position and have broad contact with the bone to which it is to be grafted. While in theory an inlay graft is best and occa- sionally it is possible to obtain a perfectly fitting inlay by the use of double bladed circular saws, in actual practice this
FIG. 1. PIECE OF BEEF-iBONE WITH STRIPS, BLANKS AND
SCREWS : A, MEDIUM SIZED SCREW, 10 BY 24 ; B,
LARGE SIZED SCREW, 5/16 BY 18
is not easy. If the blades of the twin saw are out of line there will be a considerable discrepancy in the size of the graft and the slot. It is necessary to employ some means of securing the graft to prevent it from moving. Kangaroo tendon or catgut sutures thrown about the fragments and
•Copyrighted 1020 by the American Medical Association. Re- printed by pei-mission from the Journal of the American Medical Asso-- elation, March 13, 1020. pp. 715-717.
the graft are not satisfactory. Beef-bone screws properly placed are well-nigh ideal for the purpose.
PREPARATION OF SCREWS.
Fresh beef bone is obtained usually from the tibia, the joint ends are sawed off, and the shaft is boiled for one and one- half hours to remove the tissue and the marrow. The shaft is sawed into pieces 3%, 2% and 1% inches long for the large, medium and small size of screws, respectively. The medium sized screw is of aid in many situations, and many more of
FIG. 2. INSTRUMENTS NECESSARY FOR THE PLACING OF
BEEF-BONE SCREWS : A, NO. 17 TWIST DRILL : B,
STRAIGHT HANDLED 10 BY 24 TAP; <?, OFFSET
HANDLE 1C BY 24 TAP; D, OFFSET HANDLE
WRENCH WITH HEXAGONAL HEADED BLEF-
BONE SCREW IN SOCKET; E, STRAIGHT
HANDLE WRENCH
these are used than of either the large or the small screws. The sizes used by us are standards, and in mechanical terms the large screws are known as 5/16 by 18, the medium size as 10 by 24, and the small as 6 toy 32. The lengths adopted are arbitrary and may be varied to suit the needs of the case. The pieces are sawed lengthwise into strips ; their width varies ac- cording to the diameter of the screw to be made. 'The strips are roughly sized in the vise by filing, and are then turned to the proper size, pointed, and the head rounded in the lathe. These finished blanks are placed, for one-half hour, in petro- latum brought to the melting point in a double boiler, in order to replace to some extent the natural oils removed by the boil- ing. This renders the bone a little less brittle and less likely to crumble when being threaded. The heat must not be extreme or the bone will be overheated and rendered almost chalky.
The blanks are placed in the lathe and threaded by using a standard machine screw die. Petrolatum is freely used on the die while the threads are being cut. The large blank is threaded with a standard 5/16 inch by 18 die. The head is 5/16 inch long and is flattened on two sides to % inch in thickness to fit a special wrench. The large screw when fin- ished is ordinarily 3% inches long, but this may be varied. The medium: sized blank is finished into a scrow 19/100 inch in diameter and 2% inches in length (Fig. 1). A little more care is necessary in putting the threads on this size than on the large screw, and we have found it necessary to step down the threads by using three dies : 12 by 24, 11 by 24, and 10 by 24. The small blank is for a screw 14/100 inch in diameter and \ys inches long. It is necessary to step down the threads for this screw as follows: 8 by 32, 7 by 32, to 6 by 32. The heads of the two smaller screws are % inch long and % inch in diameter to allow for hexagonal shaping to a 3/16 inch standard. These fit a specially made socket wrench fitted to
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July, 1920
SCIENTIFIC AMERICAN MONTHLY
13
the end of a small brace. When the screws are received from the machine shop they are thoroughly scrubbed with soap and water and boiled in water for thirty minutes. They are then kept in the instrument case and boiled as required, just as any instrument is boiled. The screws are cheap, easily made and well tolerated by bone. The one objection to them is that they are brittle and will not withstand any great amount of stress, particularly if there is any torsion with the strain. For his interest and skill in the actual manufacture of the screws we are indebted to Mr. Geonge Little, chief of the in- strument shop of the Mayo Clinic.
SURGICAL USES.
Even though the beef-bone screws are well made, they can- not 'bemused successfully unless there are at hand the proper instruments for placing them. Above all, it must be remem- bered that they withstand very little twisting force, and if they bind when being screwed in, they will break. For the
Chip off spinous process'
Beef-bone screw through, spvnous process and draft -
FIG. 3. CURVED TIBIAL BONE GRAFT (a) HELD SECURELY IN PLACE BY THE AID OF TWO BiEEF-BONE SCREWS PLACED THROUGH THE GRAFT AND SPINOUS PROCES- SES ■: 6, TRANSVERSE SECTION SHOWING THE REL- ATIVE POSITIONS OF THE GRAFT, SPINOUS PROCESS AND BEEF-BONE SCREW
large size, 5/16 by 18, a special socket wrench is used. I have used the large screws only in situations such as the head of the femur or the condyle of the femur. If not passed through any cortical bone, they are of sufficient strength to make their own threads in the soft hone, and the drill hole bored by a 9/32 inch twist drill does not need to be tapped. Since the medium sized screws, 10 by 24, and the small screws, 6 by 32, have a hexagonal head of the same size, the same wrench fits the two (Fig. 2, D and E). For the medium sized screw the holes in the graft and fragment are bored by a No. 17 twist drill (Fig. 2 A) and the hole is tapped by a 10/24 tap (Fig. 2, B and C). For the small screw the hole is bored by a No 29 twist drill and the hole tapped by a 6/32 tap. The drills can be used on the electric motor or on the hand drill. The tapping must be carefully done by hand. Handles of different styles for the wrench and taps will be found conven- ient for the different situation (Fig. 2, B and C). If the sub- cutaneous structures are scanty, the heads of the bone screws may be removed either by bone-biting forceps or a Gigli saw.
In recent spiral or oblique fractures of the long bones, re- cent fractures of the nock of the femur, of the olecranon proc- ess, and in certain fractures of the patella, the screws are an excellent means of obtaining coaptation of the fragments. They are a splendid means of fastening the bone graft to the spinous processes, as is necessary in the operation advanced
FIG. 4. «, TRANSVERSE SECTION OF BONE ; b, LARGE BONE GRAFT IN APPOSITION TO FRAGMENT FROM WHICH PART OF CORTEX HAS BEEN LIFTED TO PERMIT BROAD CONTACT ; GRAFT HELD IN PLACE BY BEEF- BONE SCREWS THROUGH THE OPPOSITE CORTEX ; c, INLAY GRAFT; BEEF--BONE SCREW PLACED THROUGH GRAFT AND THE OPPOSITE CORTEX
by Alhee for tuberculosis of the spine, and are the only means known to me whereby proper bony approximation can be as- sured (Fig. 3). They are not so ideal in delayed union or for ununited fractures. It has been my experience that in frac- tures of these two groups, it is best to accept no compromise but to employ a large graft so that when the operation is completed there is from 20 to 25 per cent more bone in the
FIG. 3. AT LEFT, ROENTGENOGRAM OF UNITED FRACTURE OF LOWER THIRD OF TIBIA AND FIBULA OF EIGHT YEARS' STANDING IN A WOMAN, AGED 20. AT RIGHT, FIXATION OF SAME FRACTURE BY MEANS OF FOUR BEEF-BONE SCREWS, AND PIECE OF ENTIRE THICK- NESS OF FIBULA FROM UPPER FRAGMENT. PLACED AGAINST FRAGMENTS OF TIBA
fractured region than is normal (Fig. 4). When we are deal- ing with a case of long standing nonunion of the humerus or of the bones of the forearm, the bones are often osteoporotic and smaller than normal. In such cases every surgeon of ex- perience has seen his inlay or intramedullary grafts thin out and finally break at the. line of fracture. The absorption of the graft takes place so rapidly, or perhaps it would be better
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SCIENTIFIC AMERICAN MONTHLY
July, 1920
to say that the deposition of new bone is carried on so slowly, that the graft is partially absorbed and cracks on slight stress, and a technically well performed operation in a properly se- lected case is discredited. In such a predicament the sur- geon should not be dismayed and give up all hope of obtaining union, but he should at once see that the part is thoroughly immobilized for at least two months more. In the majority of cases, and particularly if the transplant has been of good size, union will occur. I believe that the excess of bone elements brought to the devitalized area is an important causative fac- tor in bringing about union, and this is my reason for so strongly emphasizing the large graft. If the roentgen ray dis- closes very marked osteoporosis of the fragments, exercises should be instituted prior to operation, regardless of the frac- ture, because it is only by this means that the osteoporosis will be overcome. Many failures to obtain bony union are due to operating on bones that are far below par in bone salts and bone forming elements. Obviously, the simplest way to prevent a fracture of the transplant is to place a very large graft, and by this I mean large in diameter as well as in length (Fig. 4, &). The discredit of the bone graft found in some of the recent writings, particularly from abroad, is more than likely due to the author's experiences with fracturing of the grafts, the cause of which is probably the use of too small transplants.
The technic of the inlay graft will not permit the placing of a very broad piece in the fragments (Fig. 4„ c). On ac- count of failure and accidents with the ordinary intramedul- lary and inlay grafts, and the belief that it is most important to place more bone in the fractured area than is normally there, it has been my custom for some time to proceed as follows: The bone ends are carefully freshened so that as broad an area of their surface as possible will be in firm con- tact. The medullary cavity in each fragment should be opened. From one-fifth to one-fourth of the entire thickness of the bone from each fragment on one side is removed for a goodly distance above and below the fracture. This should not re- move the entire cortical wall. The graft, which is a piece of healthy bone from the tibia or the entire thickness of the fibula, flattened on one side, is greater in thickness than the amount of bone removed from the fragments, and is placed against their freshened surfaces, the ends of which are in firm apposition and the medullary cavities in line. It is held in place by two or more beef-bone screws through the graft and through the remains of the proximal cortex and the opposite cortex of each fragment (Fig. 5).
SUMMARY.
1. Beef-bone screws are a great aid in securing firm fixa- tion of the bone graft to the fragments in fractures, and of the graft to the spinous processes in the operation for fixation of the spine.
2. They are well tolerated by the bone and are gradually but completely absorbed.
3. Bone screws have not the strength of metal and must not be expected to stand great stress. Careful provision must be made for postoperative fixation of the extremity.
4. Drills, taps and wrenches of the proper size are essential for the placing of beef-bone screws.
5. The bone graft as commonly used in the intramedullary and inlay methods is too small. Fracture of the graft rarely, if ever, occurs if the graft is large enough so that when the operation is completed there is from 20 to 25 per cent more bone in the fracture area than there is normally.
that the curative action is not due to the citric acid of the lemon but to the vitamines contained in the fruit. These investigators eliminated from lemon juice the citric acid and the other organic acids it contains and found that the residue still contained the major portion of the anti-scorbutic sub- stance. Their methods were described in the Bulletin of the Agricultural Institute of Rome for December, 1919.
The lemon juice was first treated with calcium carbonate and then with alcohol and the filtered liquid, to which was added 1 gram of citric acid per liter, was then evaporated to dryness in a vacuum at a temperature below 40CC. The dry residue obtained was found to be a very active remedy for scurvy when taken into the alimentary canal. It proved in- active in the form of subcutaneous injections even in large doses. When swallowed it possesses great curative power but no preventive power. The investigators succeeded in cur- ing a monkey suffering from an advanced stage of scurvy by the aforesaid dry residue of lemon juice.
It is evident that such a preparation might be of great value to travelers by sea or land liable to be unprovided for long spaces of time with the fresh fruits and Vegetables from which most of us obtain the necessary supply of vitamines.
LEMONS AND VITAMINES. It has long been known that the juice of lemons and oranges and of the citrus family in general form an excellent remedy for scurvy, that much dreaded disease which was a former scourge of sailors upon long voyages. Recent experi- ments made by Mr. A. Harden and Mr. S. Zilva have shown
INCREASING LEAF GROWTH BY PERFORATING THE ROOT.
Prof. Mario Calvino, the director of the Agronomic Station of Santiago de la Vegas, in Cuba, has recently devised a novel device to be applied in intensive horticul- ture. This consists in making a horizontal perforation in the primary root in order to obtain a more luxurious development of the foliage in those plants which are cultivated for the sake of their leaves, cabbage, lettuce, parsley, chicory, etc. Ex- periments on parsley caused the plants thus treated to attain a diameter of 80 cm. and a height of 40 cm., while the control plants had a diameter of only 55 cm., with a height of 30 cm.
Prof. Calvino has also made some interesting experiments in the direction of increasing the yield of plants by certain injections. The Russian botanists were the first to study such effects, but it was Prof. Petit of Paris who first applied the method in agriculture. When Prof. Calvino held the position of Director of the Central Agronomic Station of Mexico, he undertook in 1912 a series of experiments to determine the practical value of such injections. An old pear tree which blossomed freely every year but never bore fruit was sub- jected to the following treatment : at a short distance above the ground the trunk of the tree was perforated as far as the zone of the fiber-vascular bundles, and a small glass tube was inserted in the hole ; this tube communicated by means of a rubber tube with the bottom of a receptacle placed at 1.5 m. above the ground and containing a nutritious solution consisting of 18 liters of water plus 19 gr. of iron sulphate plus 10 gr. of sodium nitrite. The tree completely absorbed the solution in about three days' time. The following month its leaves were found to be larger and more glossy than those of the control trees (two other old pear trees, which likewise blossomed abundantly but bore no fruit) and it proceeded to bear a considerable amount of fruit.
In 1913, Prof. Calvino experimented with another sterile pear tree but with the following solution : 20 liters of water plus 5 gr. of super-phosphate plus 5 gr. of sulphate of phos- phate plus 5 gr. of sodium nitrate plus 5 gr. of sulphate of iron. The pear tree absorbed more than 50 liters just before it flowered ; it blossomed vigorously and bore fruit.
This method of treating plants opens wide vistas. Thus it may be possible to inject in the plants the attenuated virus of bacterial organisms or to inject vegetable products such as camphor, etc., in order to produce more vigorous vegetation or, finally, to inject a solution of the substance yielded by the plant. Thus sugar might be injected into the sugar cane in order to create "the habit of the substance," thus obtaining more productive varieties.
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Courtesy of Amer. Museum of Nat. Hist.
THE LOVE MAKING OF THE PRAIRIE; HEX — A GROUP IN THE AMERICAN MUSEUM OF NATURAL HISTORY
Dancing Birds
The Art of Courtship and the Play Impulse By Dr. Kurt Floericke
LIKE the art of song that of the dance is employed by many birds primarily in the courtship of the female — perhaps indeed the latter art is even more useful as an aid in the conservation of the race, and it is found employed as a means of courtship and of the showing off of the male before the female in all kinds of birds. Secondly the dance, like the song, constitutes a challenge to a rival for the fighting of a duel, and on this account frequently ends with a more or less serious combat. Just as many birds, however, continue to sing not only in the mating time but more or less as an expression of well being, there are many birds who exercise the art of the dance at all times of the year merely to give expression to exuberance of mood, and, strangely enough it is often the most serious and dignified birds who are thus seized by the demon of the dance. Thus the crane, the king of the swamp birds, who is usually so stately and dignified is at times seized by a whim of the most extravagant abandon. When this happens the long legged fellows hop about, assum- ing the drollest positions whirling about their own axis and, in short, executing a regular dance, which excites irrepressible laughter in the beholders. In their enthusiasm the big birds take up stones or bits of wood from the ground and sling them over their shoulders, then seize them again in their heaks ; they raise their wings and altogether behave as though they were mad, yet without sacrificing any of the grace and beauty which belongs to them.
The biggest bird of all — the ostrich — is a most indefatiga- ble dancer, particularly enjoying the waltz — and a quick waltz at that ! The huge camel Decked bird whirls about with such mad rapidity that the spectator actually feels dizzy. In fact the birds themselves occasionally become so dizzy that they fall to the ground, sometimes breaking a foot.
The moor cock is another dancing bird from which the peasants of upper Bavaria have borrowed their famous "flat
♦Translated for the Scientific American Monthly from Kosmos (Stuttgart), January, 1920.
shoe dance" (clog dance). When this brilliant black bird with his red rimmed eyes and his beautiful lyre-shaped tail comes forth in early dawn upon the dewy meadows to woo his mate he first utters curious harsh cries and then a sort of muffled gobbling sound which increases in rapidity, until it becomes a wild hurly-burly in the midst of which certain crowing tones can be heard now and then. At the same time the tail is spread into a fan while the wings are raised and held away from the body, while (he head and neck, with ruffled feathers, are stretched forward ; then the cock jumps hither and thither, turns himself about in circles and presses his head so close to the earth that in course of time he actually rubs away the so-called '"chin feathers." Madder and madder grows the ecstasy of this wondrous bird, wilder and wilder are his motions, until one might think he was fairly crazy. If a second cock happens to cross his path at such a moment a heated duel ensues, which is, however, harmless in spite of the fury of the combatants. Many other gallinaceous birds behave in a similar manner. The gold pheasant, for example, is an elegant exponent of the art of dancing the minuet. He trips back and forth before his would-be mate in the most graceful positions . . . inflating his gorgeous neck and seeking by means of graceful turns and twists to display his beauty to the best advantage before his chosen one. Sad to say when his wooing succeeds he turns out to be an exceedingly brutal husband, as has been known to occur in the case of human beings!
"The mirror peacock" of Borneo, whose back and wings are adorned with brilliant green feathers edged with (bright violet, not only dances but constructs regular dancing floors so to say, since he selects in the midst of the forest at some very lonely place a suitable spot of ground and entirely clears it of all vegetation for a space of about one square meter so that it resembles a newly made tennis court ; in the middle is a small elevation upon which the cock stands to dance and display his gorgeous plumage. Among these birds
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SCIENTIFIC AMERICAN MONTHLY
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the fighting between rivals is very violent and often ends with the death of one of the combatants, since these birds are armed with two strong sharp spurs upon each foot.
The argus pheasant found in Sumatra behaves in the same way. This bird is familiar to nature lovers through the extended description made of him by Darwin. . . . This bird is distinguished from all other kinds of birds by the fact that the fore pinions are very short whereas the brachial pinions are extraordinarily elongated being at the same time broadened toward the end and weak of shaft. These remarkable feathers, whose ground coloring is a beautiful mahogany brown, are deco- rated with large iridescent eye spots with a light border sur- rounded by a darker tone ; this peculiar effect of light and shade gives a really sur- prising impression of a three dimensional plastic curving or arching. This stately bird is extremely shy of men and lives in the deepest solitude of the forests. Here each
male bird builds his dancing floor, which he takes the greatest pains to keep neat and of which he appears to be very proud. Such a dancing floor has an area of from six to eight square meters and the bird carefully removes any bit of dirt and every dead leaf which may chance to fall upon it. Except when seek- ing food the argus pheasant remains constantly upon this dan- cing place, which, therefore, constitutes his dwelling, in a cer- tain measure. So far as I know the dance itself has never been seen by human eyes, since these birds, whose far resounding cry lures the hunter to seek him, always slips silently away just in time to avoid the coming of the human being whose presence he has detected through his keen senses.
The strutting and tripping dance of the domestic turkey and peacock are familiar enough, but the wild progenitors of both these birds found in Mexico, North America and in the Sunday Islands and in the East Indies execute a beautiful dance in which the tail is spread wide, to display its full beauty. ... It must be a wondrous sight indeed to observe a scene in wild nature when a dozen or more peacocks spread their gorgeous tails and execute their dance steps. At the slightest disturbance the tails are instantly folded and the birds shoot like gleaming arrows through the sun-bright air. During his courtship and the continuing dance the turkey utters his well-known gobbling sound, at the same time scrap- ing his wings upon the ground and strutting about the turkey hen until he has won her favor.
The plover is a very elegant dancer. It begins by hovering about the desired mate on the wing, at the same time per- forming the most incredible twists and turns, throwing itself
FIG. 1. THE OSTRICH IN ITS DROLL WOOING POSTURE
from one side to the other and actually turning somersaults in the air, so that the spectator sees first the dark green feathers of the back and then the white belly of the bird. Finally it rushes down to the ground but does not immediately approach its mate, but stands off from her at a little distance and greets her with rapid bowing motions in quick succession ; then follows the actual dance during which his lady love cheers him on by uttering a peculiarly disagreeable screech ;
then the male, still continuing his dance, seizes a bit of grass or straw and throws it behind him with a graceful gesture as if delicately signifying that it is time to begin the build- ing of the nest. The excite- ment shown by the male is finally imparted to the female until slie too begins to re- spond by uttering cries and taking dancing steps until the pretty play comes to an end. In Central Asia I also saw the "stilt-runner," an elegant little snipe with incredibly long red stork legs, executing its hopping dance with hori- zontally outspread wings ; because of the long legs of this bird the dance looks very comical and awkward. While our com- mon snipe {acolopax gallinago) carries out its courtship en- tirely in the air, making meanwhile the well-known goat-like bleats which characterize it, its near relative, the Gallinago media, does its wooing upon the ground. (Fig. 2.)
In the evening twilight S or 10 of the males or even more gather regularly vipon the same spot in a marsh meadow which can be recognized as their dancing floor by the downtrodden grass. The females stand around as specta- tors while the males dance back and forth before them with their plumage ruffed up while they alternately spread and close their tails like a lady's fan, at the same time uttering soft and tender notes interrupted by violent snapping of their bills, and showing by their whole demeanor that they are in a condition of rapturous exaltation.
The stately curlew I have also learned to recognize as a dancer and dancing the galop at that ! This bird runs rapidly forward in a straight line with head and neck pressed close to the earth while uttering an almost unbroken suc- cession of its magnificent flute-like trills.
Social dances are executed by the splendidly plumaged Tanager (Tanagridae) birds in the primeval forests of South America. Almost each kind has its own peculiar dance. One of these reminds one strongly of the well known children's game "puss in the corner." A number of birds take their places at definite spots while one of them stands in the middle and sings. When a certain note is heard in bis song all the birds instantly change places, trying to secure another location.
FIG, 2. SNIPES AT COURTSHIP
FIG. 3. DANCING CRANES
FIG. 4. BUILDING A DANCE BOWEK
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SCIENTIFIC AMERICAN MONTHLY
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The one left out proceeds to the center and begins to sing the same song.
THE PLAY IMPULSE.
This example is evidently an instance in which the dance becomes an expression of the delight in play, which is an ex- tremely strong instinct in birds, on which account the owners of caged birds should take care always to give their pets some opportunity to exercise their playful activities. One need only observe a troop of sparrows who have found a smooth slide somewhere to see how they make merry with it.
Likewise in the primeval forests of South America but exclusively in well watered rocky valleys of the mountain side lives the marvelous helmet crowned and scarlet clad cliff bird. As we know from Schomburgk's classic representa- tions this bird makes use of flat rocks as dancing floors. Upon such a place great numbers gather while one of the males executes a solo dance during which it makes all sorts of playful motions, scratching the hard rock with its feet and spreading its tail into a fan. When it becomes tired it utters a definite cry never heard at other times and makes way for a new dancer to entertain the crowd ; the females meanwhile receive the retiring performer with loud cries of applause.
Our lapwing handles his fan in a masterly manner while dancing. His fan is not his tail but the beautiful crown of feathers which adorns his head and which he knows how to close and half close with the greatest grace while wooing his mate with tripping dance steps.
A very graceful dancer, too, is the mourning stonechat which I have often observed with the greatest delight in the wildest mountain regions of Spain, where this bird, whose plumage is intensely black but relieved by the dazzling white of his vary- colored tail feathers, lends more vivacity than any other crea- ture to the melancholy sunburnt landscape. He dances trip- pingly about upon the cliffs, constantly changing his position, however, and one never grows tired of watching his nimble and graceful movements.
Most kinds, too, of the "love birds," those gay little tropical birds which were so popular among our bird lovers before the war, and were successfully bred by some of them, must be counted among the dancers. Many of them have the same habit as that of the plover of seizing a bit of grass or straw in the beak while dancing and many of them, too, perform a series of rapid and energetic bowing motions. Among most of them the dance consists merely in an incessant hopping up and down upon the same spot, accompanied by a monotonous and unattractive sing-song sound.
Among the marvelous paradise birds of New Guinea the special object of the dance is to display the fabulous beauty of the male. The bird places itself upon the dry top of sin old tree — often many of them at the same time — and utters peculiar quacking sounds, while at the same time opening and shutting the splendidly colored tufts of feathers at his sides and erecting the long and waving ornamental feathers until they look like a comb. It is a magnificent sight and the bird always endeavors in the most vigorous dancing to preserve from injury the delicate plumes which adorn him. A very remarkable biological observation in regard to this has been recently made to the effect that since the males are shot in such large numbers because of their valuable plumes there has come to be an excess of females, in consequence of which, in a great many cases, the female takes the active part in the courtship instead of the male. To be sure the female paradise bird is a most uncomely and unattractive creature and so her dance is lacking in that intriguing charm which surrounds the male clad in his glorious plumage.
Among the relatives of the paradise bird are the bower birds found in Australia and New Guinea, which are remarkable in that they erect real dance bowers of leaves and seem to at- tach great importance to the decoration of these places. The silk bower bird, for example, builds upon the ground in some
lonely spot in the wood a roof-like bower out of twigs, etc., which has an open entrance on each side (as shown in Fig. 4).
The walls of this structure are decorated with all sorts of gay ornaments, such as parrot feathers, red berries, green moss, bright flowers, etc., which are always replaced by fresh ones when the original ones have withered, while the old material collects in a rubbish pile behind the bower. At the front door of the bower a special decoration is placed composed of bright colored mussel shells, bones bleached white, prettily colored stones and pebbles and glittering and unusual articles of all sorts, often in really astonishing quan- tities. Likewise in the still more artistic bower more than a meter long built by the Kragenvogel there is not infrequently found half a bushel of bones and mussel shells. In their choice of these decorations the birds are very fastidious and it has been discovered from an examination of the shells found that they are sometimes brought from a distance of a mile or more. The bower birds, like the bird of paradise, belong to the group of the ravens, and have well marked thiev- ish instincts like our own ravens. The "gardener bird" builds itself a circular bower with a spherical supporting column made of moss while the walls are made of orchid stems. In front of the bower the bird clears a special dancing floor and executes his courting dance inside and outside of the bower until a female is induced to enter.
Among our domestic song birds there are also a few zealous and admirable dancers. I remember with especial pleasure, for example, a blue-throated warbler which I kept for a long time in a cage. During the mating season this bird danced with its head bent far backward so that the inflated blue neck was beautifully displayed ; the tail was spread into a fan and the wings were held downward while the performer turned round and about in the rhythm of a waltz. The most curious and remarkable thing about this bird was that it quite ob- viously took great pleasure in having me share its dance, so that when I wished to incite it to dance I had only to do a bit of dancing myself in front of its cage. This graceful exer- cise was usually ended by the gift of a special dainty in the form of a nice fat meal worm to my dancing partner.
THE COURTING ANTICS OF THE FLY. An entertaining account is given by a German naturalist, named Erwin Lindner, of the curious "dance" made by a fly (Chloria demandata Fabr.) which he happened to see on a sunny garden bench in Semendria. The time was five o'clock in the afternoon, November 1st, 1917. The female fly was resting upon the bench occupied apparently solely with making her toilet. The male fly, on the contrary, was obviously in a state of great excitement, executing a mad sort of dance in front of his would-be mate. Now he would stand off at a little distance from his lady love with his head turned toward her, and now he would encircle her several times, dancing about her at a distance of a few centimeters. Usually, how- ever, not completing the circle — but before finishing it — run- ning in the direction of a chord of the circle toward her head, stopping short then, for an instant, and making some remark- able sidewise movements. Finally, he raised the left front leg and rapidly stroked the head of the female with it. Then he made another circle about her head, repeating this a great many times with increasing rapidity. The female remained motionless most of the time but suddenly rushed at the male seizing the end of his body with her forelegs, apparently striving to hold the male fast while he struggled to get away but without moving his wings. Then the two separated, the female went back to her old place and the male began his waltz about her once more. First he danced about her, then swiftly turned about, ran toward her, raised his left wing so that its point almost touched her and waved it rapidly. The female ran away repeatedly followed by the male, but always came back to her former place, until the courtship was finished.
Producing Flies with Horns*
Remarkable Experiment in the Artificial Modelling of the Chitin
By Rene Merle
AT a meeting of the Academy of Sciences which took place upon the 10th of last November, Professor Cuenot of the Faculty of Sciences of Strasbourg presented a very interesting note upon the reciprocal adaptation of the forelegs and the head among the Phasmids.
It is a matter of common observation that in a large num- ber of these insects the upper portion of the forelegs is hol- lowed out on the side next the head. During the daytime while the insect is at rest the forelegs are extended towards the front and clasp each other in the line of the body, thus forming between them a narrow, rigid sort of trough in which the closed antennae rest. In this position the aforesaid curve of the thighs (femurs) exactly fit the outline of the head beneath the eyes, which remain uncovered. The two other pairs of legs do not have this shape. This peculiar formation is found not only in the Phyllida, but in the Bacillae and the Carausius. In all of these the adult insect fre- quently extends its forelegs with the head hidden between them, thus looking like a bit of stem ; it has been supposed that this attitude helps to con- ceal the insect from the eyes of its enemies, and conse- quently to protect the species ; this, in fact, is one of the most commonly cited in- stances of protective mimicry.
There has been a good deal of debate with regard to the mechanism of this neatly fit- ting curve in the forelegs for the reception of the head and antennae, a peculiar "form which exists from the very moment of birth, when the young creature issues from the shell.
Professor Cuenot points out that even if the clasping of the forelegs is a detail which is of some utility with regard to defense, it is nevertheless quite evident that this utility could not have existed until the shape of the legs had attained its present state of perfection, whereas it is impossible to con- ceive of a process of slow variations during which the law of selection would favor those individuals whose legs, b.v reason of some chance variation found it possible to appreach each other near the median line. This, in fact, is the very argument raised by objectors to Darwin's theory of the con- structive role played by natural selection, an objection based upon the idea of those organs which are of no use until they have arrived at a perfect state. It is obvious that the early stages must have been entirely without utility, and, consequent- ly, could have played no part in determining natural selection.
"Neither is it possible to believe in some chance mutation which happened to produce the mutually adapted arrangement of the legs and head, followed by a selection favoring the mutants as being better protected than the non-modified Phasmids.
•Translated for the Scientific American Monthly from La Nature (Paris).
ARTIFICIAL, AND NATURAL MOLDING OF THE CHITIN 1. Normal head of the FucelUa caritana. 2. Head after artificial formation of horn. 3. Curved forelegs fitting around the head of a phasmid.
"For their part, the Lamarckists would say that the Phas- mids, experiencing the need of clasping their legs together in front of them, made such strenuous efforts to accomplish this that the comparatively plastic anterior femurs became curved by pressing against the head, and that after a certain number of generations this curvature became fixed in the ontogenesis, so thoroughly as to appear in the embryo at the present time without any connection with the mechanical cause which occasioned its development in the Phasmids after hatching."
As a matter of fact, neither of these interpretations is satis- factory and as it happens the real cause of this phenomenon is far more simple. This curvature of the legs does not exist in the embryo : it makes its appearance only after the in- dividual has been hatched from' the shell and is occasioned
by a very simple mechanism closely studied by M. Cuenot in the Carausius morosus. At the moment when the insect escapes from the shell its body curves upwards and the top of this curve makes its exit first, the head, antenna3, the legs, and the end of the abdomen remaining still with- in the shell. The region of the head then disengages it- self, but remains wedged be- tween the thighs of the fore- legs. At this moment the chitin of the legs is still soft, whereas that of the head is already considerably harder. Consequently the head makes an impression upon the chitin of the legs and these become molded to fit it. When the insect has completely emerged the chitin becomes tough and resistant everywhere, but by that time it has already ac- quired the remarkable form which has caused the shed- ding of so much ink. It is evident, therefore, that the perfect adaptation which ex- ists between the shape of the legs and the head and antennse which they surround has no decisive significance ; it is merely a molding of the chitin which takes place during the act of hatching.
As a result of these observations Professor Cuenot holds that "this phenomenon is due to a fortuitous mechanical ac- cident, entirely independent of any question of utility or of custom ; the animal takes advantage of this accident to assume during the daytime a special attitude which happens to be convenient for repose, or advantageous from the point of view of camouflage ; but it must be remembered that it is the mutually adapted arrangement of the head and legs which de- termines the attitude and not the attitude which occasions the arrangement."
This peculiar plasticity of the chitin at the instant when the metamorphosis takes place has attracted too little at- tention heretofore. It is, however, a very remarkable cir- cumstance, for Professor Mercier of the Faculty of Sciences of Caen has been able to make use of it to produce actual monsters, horned flies, as related by him in the Comptes
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Rendus of the French Society of Biology, November 29, 1919.
He happened to find in the littoral zone at Lac-sur-Mer certain Diptera, the Fucellia caritana, among which one in- dividual had a small horn between its eyes. In order to find out what could have produced this malformation he attempted to reproduce it experimentally. For this purpose he placed pupae of this insect in small glass tubes of such a diameter that an adult fly could not turn around in them, the tubes being closed at each end by a plug of cotton wadding.
"After hatching," says he, "the flies which had issued from the pupae sought to make their exit from the tube. They blew up their frontal vesicle and inserted it between the plug of cotton and the wall of the glass tube, endeavoring thus to open a passage way. The vesicle could plainly be seen to ex- pand and then to contract. This action continued for five or six hours at the end of which time, under the influence of the phenomena of oxidation which occur, the chitin which
covers the body assumed a deeper tint of brown and became more tough and resistant. The contractions of the frontal vesicle became less frequent and less rapid, until a moment occurred when the vesicle expanded for the last time, but was too stiff to contract, and, therefore, remained in the form of a small protuberance which finally became an actual horn."
Here then we have another case in which the chitin is shaped into a definite form while still plastic, but this time the form is of no use to the animal.
These two observations occurring almost simultaneously show how much there is still to be learned with regard to the metamorphoses of insects. A study of the mechanical condi- tions involved in the act of hatching would certainly reveal numerous facts of the same kind and throw much light upon these questions of mimetism and of adaptation upon these problems which are still so obscure and often so poorly formulated.
Artificial Siamese Twins*
Remarkable Results of the Experimental Union of Two Animals
By Dr. Max Heyde
THE term "Parabiosis" is the name given in 1908 by Sauerbruch and Heyde to a form of experiment in which two animals of the same kind were united by means of an operation. The technique of this artificial union was managed as follows : The skin of the animal was split along a line running along the right or left flank from the upper foreleg to the hollow under the shoulder, and the skin was then separated from the tissues beneath so as to be movable. In most of the experiments the abdomen was then opened and the edges of the peritoneum sewed together in the usual manner of an intestinal anastomosis. In another series of experiments the investigator avoided this operation and contented himself by making a continuous lateral seam between the muscular layers of the rump and uniting the edges of the skin above and below this union of muscles. It was found unnecessary to make use of a bandage to retain the position, all that was required being to keep the two animals for a short time in a narrow cage.
The healing of the wound thus made occurred in from eight to twelve days. In certain cases where there had been a neglect of the proper conditions there occurred sloughing off by means of suppuration, and in some instances this made its appearance even after a week of apparently good results. From a histological point of view the healing of the wound was remarkable for the comparative strength of the granu- lation tissue formed upon each side. This fact is probably to be referred to the effect of a foreign body. After a longer duration the parabiosis exhibits only a narrow white scar at the place of union, which can be recognized in a microscopic section by means of a slight sub-epithelial lymphocytic infil- tration and by the lack of the hair follicle and its glands. In the earlier stages of the process of healing a direct uniting can be observed taking place between the ends of the capil- laries of the two animals. It was observed, too, after the separation of the living animal from a partner which had died, in which case a little bit of the tissue of the dead animal had been retained, that there was some genuine bleeding from the blood vessels in the neighborhood of the place of union. The union between blood vessels is shown with especial beauty in the injection preparations made by Goldmann and Zapelloni, so that there can be no doubt of a direct communi- cation between the blood vessels in spite of the opposite view held upon this point by Morpurgo, Ranzi, Ehrlich, and others.
A union by means of the lymphatics is incontestable. Fur- thermore, there is a direct exchange of the fluids of the body
"Translated for the Scientific American Monthly from Die Natur- wisscnschaften (Berlin), February 5, 1915.
between the two animals in the case where the abdominal cavi- ties are united. Finally, it is possible that there is also a certain amount of diffusion from the capillary loops. On the other hand, nerve connections are entirely lacking, it re- sults from this that these series of experiments are chiefly adapted to throw light upon pathological conditions upon questions concerning some toxic effect, where the reflex ac- tions are excluded.
The united partners, therefore, form to a certain degree a single individual similar to the occasional freaks observed in nature, such as the Siamese twins, or the Blaczek sisters, whose case attracted general interest some years ago by rea- son of the pregnancy of one of the sisters.
All these experiments may be considered as falling in general under the head of grafting of tissues, and their final conse- quences represent the grafting of an entire organism upon another instead of a limb, a tissue or an organ. But these experiments of ours differ from all former ones by reason of the fact that by means of this parallel union between two or- ganisms we obtain a means of investigation assisting us in the study of the widest variety of problems in the realms of clinical and experimental physiology and pathology.
It was not by mere chance that we were unable to carry these experiments further. At that time the knowledge of the conditions required for the successful transplantation or grafting of animal tissues and organs was still very limited. It was especially true that the conditions involved in ex- periments upon the usual animals employed for research, ap- peared considerably more complicated than in the case of lower forms of life, among which analogous experiments have often been conducted by zoologists such as Korschelt, Joest, Cor- rens, and others. Indeed, it is not very long ago that the possibility of transplanting tissues of a different kind from an animal to a human being was seriously debated, as was also the question of heterogeneous blood transfusion. Growing experience, supported by careful observation (Landois), has indicated the futility and even danger of such practises. Re- cent studies have shown us that heteroplastic experiment is practically never successful, while homeoplastic experiment, in the case of the grafting of tissues from one human being to another, is only occasionally successful. As a rule it far more often happens that the transplanted portion perishes and is either absorbed or sloughed off by means of granulation and suppuration. (Upon this point the interested reader may consult Schorne. Die Heteroplastische und homoioplastische Transplantation. Springer, Berlin 1912). Sometimes indeed in such cases, there is an injurious effect in the form of
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a toxic action upon the grafted subject. This fact is probably to be explained by modern views as to the chemistry of al- bumens and the use of serums. These teach us that the higher organisms represent thoroughly individual biological entities, which refuse to permit any heterogeneous element to remain in their community of cells. However, these limitations due to individual peculiarities have been broken down in a very remarkable manner by means of our series of experiments in parabiosis. By means of this we succeed in forming a definite union between two of the higher animals for a long period of time.
It follows as a necessary result of this experimentally ob- tained condition that after the healing of the wound the ani- mals thus connected must exert a mutual influence upon each other. From the anatomical and physiological point of view they remain separate individuals so far as their special func- tions are concerned, yet at the same time they constitute a new individual entity.
Attempts have not been lacking to make this union even more intensive by making use of the modern methods em- ployed in the surgery of the blood-vessels. Not only Hedon, but more especially Enderlen and his collaborators have ex- perimented along this line. Particularly interesting was the discovery that after the uniting of the artery and the vein at the neck no reciprocal toxic action of the companions was perceptible. If a thrombosis occurred at one point of the seam one of the animals lost all its blood to the other. Enderlen considers it improbable that there is a homogenization of the two individuals in the sense that biological differences in the plasma of the cells of the body are wiped out. But it must be remembered that in these experiments the duration of the union was very brief. The mutual interdependence of the two animals was exhibited by various phenomena worth mentioning. The death of one inevitably caused the death of the other. A sloughing off of the dead from the living by means of suppuration never took place. Such phenomena as increasing weakness, signs of irritation, and even at times convulsive movements (cramping) are to be regarded as due to the absorption of the toxins formed. This corresponds to the fact discovered that various substances when introduced into the body of one of the partners soon began to take effect in that of the other.
Another thing observed was that after such artificial Siamese twins had been united for some time serious disturbances of nutrition took place which were entirely independent, as Morpurgo has shown, of the food taken. They are first ex- hibited in the differing rate of growth of the two components. Later grave alterations occur. While one of the partners develops with remarkable rapidity the other displays signs of intensive starvation. The layer of fat disappears, that of muscles grows continually weaker, until finally the feebler partner resembles a mere appendage upon the stronger one. Morpurgo and Schoene remarked the same thing. The former observed in a male and a female rat thus joined, and which previously exhibited little difference, that 19 days after the operation the stronger animal was UV2 cm. long. The skull of the first was 38 mm. long and 20 mm. wide, while that of the second was only 34 mm. by 16 mm.
These observations are all the more remarkable since a primary difference due to the taking of different amounts of food was carefully avoided. Accurate experiments by Mor- purgo and Lombroso have proved that aside from a slight ex- change of nitrogenous substances a reciprocal mingling of nutritious materials does not take place. It was always found, too, that the duration of life and the loss of weight in a starving partner did not differ from the same phenom- ena in a starving individual not thus united. The fact of this strikingly different rate of growth, therefore, must be regarded as connected with the condition of parellelism, as has sometimes also been found the case in instances of human freaks. In these likewise we often see the state of health grow continually worse, while the other develops with un-
common vigor. In such a case the well-developed partner behaves like a parasite upon the weaker member of the union.
Ehrlich, Sauerbruch and Heyde have sought to explain this surprising state of affairs by means of the researches with regard to athreptic immunity. According to this view the phenomena can be explained by supposing that the animal which is the stronger one to begin with draws towards its own body certain substances "required for its development — perhaps also the elements of nutrition in general — and thus to a cer- tain degree passes sentence of death by starvation upon its companion. But even if we admit this possibility to be cor- rect it by no means explains the frequent occurrence after a short time of violent disturbances of health, especially in rabbits and guinea pigs, which exhibit all the symptoms of a case of acute poisoning.
It is noteworthy in this connection that, according to the researches of Eller, the serious clinical symptoms which ap- pear include alterations in the blood which must probably be ascribed to toxic influences. Such cases give the impression that the two animals are not biologically suited to each other. Differences in the composition of the albumen and a high degree of sensibility with respect to intestinal (parenteral) assimilation of such substances may probably be looked upon as the cause of such pathological symptoms. As to whether any anaphylactic effect is concerned herein cannot certainly be stated at the present time.
In order to exclude these biological differences between two parabiotic animals so far as possible, thus avoiding one source of possible ill success Sauerbruch and Heyde advise the experimenter to make use as far as possible of animals of the same sex and the same litter. In any case they hold that these precautions lead to better and more uniform results.
CHIEF FEATURES OF THE SERIES OF EXPERIMENTS
Taking the idea of transplantation or grafting as our start- ing point it became our first object to discover by means of this parallelism the extent to which the original condition or disposition of one of the two companions could be transferred to the other. Of special importance appears the question whether a definite alteration can be produced in a given or- ganism by uniting it with another. If this be true it might be hoped that surgery would gain assistance from parabiosis. However, it has not yet been possible to come to any definite conclusion upon this point. To begin with the idea suggested itself to test in this manner the conditions required for heal- ing in the case of grafted pieces of skin, but decisive results have not yet been obtained by Schoene in experiments along this line.
Under the same head fall very interesting experiments with respect to the possibility of transferring immunity from cancer or susceptibility thereto. At the time experiments made by Krauss, Ranze and Ehrlich showed that in the case of parabiosis between a rat having a tumor and a normal animal the latter did not become affected. Albrecht and Hecht also found that parabiosis exerted an inhibiting in- fluence upon the growth of a tumor in a mouse.
Lambert proved that an animal might be entirely trans- formed by long continuation of the parabiotic condition. Mouse tumors which ordinarily do not grow upon rats ex- hibited an' excellent development upon rats joined to mice by parabiosis.
A number of other investigators have sought to discover to what extent disturbances in the progress of specific or- ganic processes in one partner can be recognized in the other. Especial efforts have been made along this line in the study of disturbances occasioned by some injury or alteration of the internal secretions. Most important of these experiments are those concerning compensation in the case of the kidneys as carried out by Morpurgo, Sauerbruch and Heyde, and their collaborators, Jehn and Birkelbach. These experiments have done even more to explain the cause of uremia than the fact demonstrated by Morpurgo, that in the case of two united
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rats the kidneys of one partner are capable of functioning for the other partner for months at a time. We cannot here elaborate this difficult chapter of our experiments, but will merely mention that they involve interesting discoveries with regard to the formation of oedemas, the cause of the hyper- trophy of the heart and the problem of the internal secretion of the kidneys.
Sauerbruch and Heyde have also tried to find out whether it was possible to find an explanation of the beginning of birth pangs by studying the process of parturition in the case of two animals thus united. In the course of these investi- gations they made the surprising observation that shortly before the beginning of the pregnant animal's throes, the normal animal became extremely ill, and, indeed, perished in convulsions while the pregnant animal remained well. The investigators came to the conclusion that at the end of the period of pregnancy certain substances, probably of a specific nature, make their appearance, which are non-poisonous to animals in an advanced state of pregnancy, but are extremely toxic to normal animals, occasioning a violent death. They be- lieve too, that these specific substances are capable of occa- sioning abortion at the beginning of the period of pregnancy.
Under the same head, finally, are to be classed the experi- ments made upon frogs by Harm with respect to the produc- tion of secondary sex characteristics. Harm based his in- vestigations upon the hypothesis that the genital glands may secrete substances which are of importance with respect to the development of definite sex characters. He also studied the problems as to whether the influence of the testicle upon the phenomena of rut depends upon an internal secretion. In these experiments he united a normal animal with one which
had been castrated. He thus demonstrated that certain phenomena of sex which are lacking in ordinary castrated animals, such, for example, as the yellow color of the fatty bodies and the clasping reflex were retained in the parabiotic castrate. On the other hand the atrophy of the glands, as also the tubercles of the epidermis, the so-called "thumb cal- louses," were not prevented.
While the experiments described above have concerned physiological problems rather than pathological ones, at the same time they have thrown light upon the cause of death from uremia, from severe burns, and from contusions. These experiments alone have been able to give a definite answer as to whether temporary pathological symptoms are to be referred to a reflex or to a toxic action. The proof of the latter is shown by the illness of the second partner which had not been artificially injured. These results were parti- cularly important for the understanding of the causes of death from burns (Heyde and Vogt) as also death from in- testinal stoppage (Sauerbruch and Heyde) which were form- erly attributed to various causes, reflex action especially be- ing responsible for the first symptoms of disturbance.
We may also mention briefly the work done in this man- ner with regard to the origin and transference of poisons of an external nature, the transferability of the tuberculin re- action or of anaphylactic poisoning and the formation of anti-bodies (Friedburger).
I trust I have succeeded so far as it was possible within such limited space in proving that the series of experiments made possible by parabiosis form an excellent means for the study of weighty problems — a means capable of leading to other important conclusions.
Turtles, Terrapins and Tortoises
Reptiles Whose Flesh and Eggs are Prized as Table Delicacies
By May Tevis
Photographs from the American Museum of Natural History
A GOOD many people doubtless will be rather startled to hear that turtles and their relatives, the terrapins and - the tortoises are really reptiles. Most persons regard snakes with both fear and abhorrence, partly because of the deadly venom so many of their tribe possess, partly because of their sly, surreptitious methods of attack, and partly no doubt, because of subconscious associations connected with the original indiscretion of Mother Eve. Turtles, on the contrary, are generally regarded not merely with tolerance but even with. esteem and affection, and this not merely be- cause of their succulent appeal to the palate but likewise through subconscious associations somewhat more obscure in character. Whatever the reason may be, the turtle family has for centuries been held in high regard in many parts of the world. Perhaps this is partly because of their very solid and dependable structure. Is it not in the Upanishads that the world was represented as resting on the broad and steady back of a great turtle — surely a more dependable basis of support than even the mighty shoulders of Atlas? Then, too, these creatures enjoy a tremendous reputation for steady determination of purpose and unflagging energy in carrying it out, as witness the ancient fable of the hare and the tortoise. In short, they are looked upon as symbols of the eminently desirable virtues of patience, prudence, and perseverance. The writer has in fact seen these qualities amusingly repre- sented in baby loggerheads just out of the shell, scrambling up through the warm Florida sands which form their incu- bator, and heading straight for the ocean in spite of various attempts to divert them or bar their way with obstacles. And who that loves his Uncle Remus can fail to have a kindly feeling for old Brer Terrapin?
Then, too, the majority of people consider the idea of
eating the flesh of reptiles as being repellent and even dis- gusting, whereas the flesh of many members of the turtle family is a highly prized delicacy. Green turtle soup is famous all over the world and terrapin are fairly worth their weight in gold, selling even before the war at the rate of $75 a dozen for specimens 8 inches long (according to Mr. Dittmar, though 'the writer has found small ones recently at 75c), which makes it amusing to recall that they were once so plen- tiful in the waters of the Delaware that the slaves upon the nearby Maryland plantations petitioned for relief from a too constant diet of venison and terrapin.
However, turtles, terrapins and tortoises are true reptiles according to scientific definition, since they are cold-blooded vertebrates which breathe by lungs throughout their whole existence and not by gills during a part of the time as do the likewise cold-blooded and vertebrate animals, frogs, toads and other Batrachians. Unlike Batrachians they undergo no change of form, coming from the egg in the same form which they retain throughout their lives. Furthermore, the skull of these animals is joined to the backbone by a single rounded knob or condyle, which is characteristic of reptiles as well as of birds, whereas in Batrachians as well as in mammals there are two of these rounded knobs or condyles. Again in the great majority of reptiles the skin is covered with scales or shields, while in most Batrachians it is naked.
CLASSIFICATION.
In the preceding paragraphs I have used the word turtle somewhat loosely to include their congeners, the terrapins and the tortoises, and the word turtle is, in fact, generally so used in this country. Strictly speaking, however, it is better to confine the word turtle to those members of the Chelonia
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SCIENTIFIC AMERICAN MONTHLY
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WAX CAST OP A PAIR OP FIGHTING SPOTTED TURTLES
(Greek, Chelonium = a shield) which live exclusively in water and possess paddle shaped limbs ; the purely terrestrial members of the Chelonia having club shaped limbs, are properly called tortoises, while those which live both on land and in water and possess an intermediate form of struc- ture are terrapins.
The body of these animals is protected by a bony shell, usually coveed with horny shields, into which the head, neck, limbs, and tail may be retracted. This shell is composed of numerous bones, the principal being expansions of the vertebrae and ribs, forming the carapace, or dorsal buckler, the neck and tail being the only movable portions of the spinal column, and clavicles and abdominal bones forming the plastron or ventral buckler. The carapace and plastron are usually connected by a lateral part known as the bridge. Both the bony plates and the horny shields on the shell afford excellent characters for the purpose of classification.
In some tortoises and terrapins perfect hinges of elastic ligament are formed across the plastron, as in the so-called Box Tortoise, and either the anterior or the posterior lobes, or both, as the case may be, are movable and close up the shell. In the genus Cinixys a similar hinge is situated across the carapace, the hinder part of which is movable.
Regeneration of lost parts does not take place, although, as Gadow has shown, the injuries to the shell are made good by new growth of bony and horny tissue, after the dead portion has been cast off.
A tail is always present, but differs much both in length and structure, according to genera and species, this organ being sometimes covered with horny or bony tubercles, while in many the tip is provided with a sharp, nail-like spur. The toothless jaws are covered with cutting "horny sheaths which may be serrated and constitute pseudo teeth. The neck, which varies much in length, may be either completely or only partly withdrawn into the shell, in some forms simply sideways (Pleurodira), or by a sigmoid curve in a vertical plane (Cryptodira) . The eye is rather small and protected by an upper and lower lid, and a transparent membrane (the nicti- tating membrane), which moves horizontally; the pupil is' always round. The sight and senses of taste and touch are well developed, that of hearing, however, is very imperfect, especially among aquatic forms, some of which are devoid of an exposed tympanum or ear-drum.
All tortoises, terrapins, and turtles lay eggs which may be round, oval or elliptical, and are generally hard-shelled ; ma- rine turtles, however, produce eggs, the shell of which is leathery instead of hard ; they are always buried in the ground and hatched by the heat of the sun. Hibernation takes place in the temperate zone, the period varying in length according to the climate. Aquatic species generally hibernate
at the bottom of the ponds or rivers they live in, or in the mud on the banks, while the land forms secrete themselves in the earth and sand, a few constructing regular burrows which may extend to a depth of several feet.
The food varies according to the structure and the mode of life. Land forms are vegetarians, those frequenting the water are either carnivorous or herbivorous, a few only living on a mixed diet.
Tortoises are remarkably long-lived, the giant forms of the Aldabra and Galapagos Islands attaining an age unparal- leled by any other animal.
The order is not a very large one, the number of species of Chelonian amounting to only just over 200.
LEATHEKBACK TTJKTLE.
The Dermochelys coriacea, of the family Sphargidae, is the only representative of the suborder. It is the largest of liv- ing chelonians, and differs from all other turtles, terrapins, and tortoises in that its vertebrae and ribs are entirely free, and not fused with the carapace. The body is protected by a shield of small mosaic-like bony plates, covered with a very thick layer of leathery skin, which, except for the presence of a number of longitudinal ridges, is in adult specimens per- fectly smooth ; in the young it appears rather tuberculate. The limbs are paddle-shaped flippers without claws, giving the animal great swimming powers, and enabling it to venture far out to sea. In color it is dark brown, often more or less distinctly spotted with yellow or looking as if splashed with whitewash.
This creature has been considered to represent, so far as its vertebral column is concerned, the primtive type out of which the ordinary tortoise has been evolved says Boulenger, it being believed that the ossifications underlying the skin have gradually become fused with the bones of the skeleton to form the shell of tortoises and turtles proper. Others be- lieve the Sphargidae to represent an ultra-specialized type evolved out of the turtles.
The Leatherback Turtle has a world-wide distribution, and is, in fact, a pelagic animal, straying to very distant localities, occasionally visiting the coast of Great Britain. In spite of its wide range it is by no means common. Numbers have been seen, however, off the coast of Tenasserim, and at the entrance to the Klang Straits, where they gather in order to deposit their eggs, each female depositing some three or four hundred.
The strength and pugnacity of this turtle are indicated by the following account by G. W. Gourley, of the capture of a specimen at Santa Barbara in the year 1905.
"The turtle was first seen swimming on the surface about two miles off shore. I went after it, accompanied bv a boy,
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in an eighteen-foot sailing boat. On approaching the turtle I dropped the tiller and got forward with the gaff hook, swung over the side, and got the hook fast in the leathery part of the neck. He immediately sounded, and ran out the full length of the line — about two hundred feet — towing the boat about half a mile farther out to sea. He then came to the surface and we pulled up close to him again. When he caught sight of the boat he turned and came towards us
AUSTRALIAN SNAKE-NECKED TURTLE
and threw his flippers over the gunwale of the boat, nearly capsizing her. I climbed up on the upper side, and shoved him off with an oar, the end of which he grabbed and bit off like a piece of cheese. His movements were very swift ; using his fore-flipper he could turn almost instantly from one side to the other, and his head would project about eighteen inches from the body. I succeeded at last in throwing a noose over his head, and later, by attracting his attention in the opposite direction, got ropes round both flippers, fin- ally having five lines on him, and started to tow him towards the shore. We were from 11 :30 A. M. until 4 P. M. in finally landing him. When about half-way to shore he suddenly turned, and made a break out to sea, towing the boat stern first, with all sail drawing full, for several hundred yards, with little effort. He emitted at intervals a noise somewhat resembling the grunt of a wild boar."
The largest specimen on record is over eight feet in length and weighs just over 1,500 pounds.
Snapping turtles.- — Snapping turtles, sometimes called alliga- tor turtles, have enormous heads, strongly hooked jaws, a long tail, a chin provided with fleshly appendages, and a very small cross-shaped plastron. One variety, Macro clem/rays, sometimes attains a length of nearly six feet. This turtle while sometimes found in the southern states is most abun- dant in the Mississippi and the streams which flow into it. It has one very striking peculiarity, namely, a number of white fleshy appendages of the mucous membrane situated just in front of the tongue, which, the mouth of the creature being kept open, when in the water, are moved in such a manner as to simulate living worms, with the evident object of attracking the fish it lives on.
All these turtles are notorious on account of their savage dispositions. When annoyed they rise on their hind legs and turn almost complete somersaults in their efforts to bite. Ac- cording to Holbrook they live at the bottom of stagnant pools or rivers of sluggish motion, occasionally coming to the sur- face With the rip of their snouts elevated, the other parts concealed, and in this manner float about aimlessly, descend- ing to the bottom again when disturbed. They are much esteemed as an article of food, and large quantities, at least in North America, are brought to market. They are com- mon in sea-food shops in New York City. They do exceedingly well in captivity, two "Snappers" in the collection of the Zoological Society in London, received nearly fourteen years ago, are almost as ferocious as on arrival, says Mr. Boulenger, the director, and will still occasionally seize upon walking- sticks and such articles as may be offered them "for the pur-
pose of inducing them to show off their uncontrollable tem- pers." These specimens are fed exclusively on meat. In their native land they feed principally on fish and small waterfowl.
In the family Cinostemidae, popularly known as mud terra- pin, the anterior and posterior lobes of the plastron are mov- able and connected with the central part by hingesi, so that their oval-shaped shell can be partly or completely closed. The mobility of the plastron varies considerably to species and with age, for, as in the case of all terrapins with hinged plastrons, the mobility is not so marked in the young. The species most frequently seen in captivity are the Pennsylvanian mud terrapin, C. Pennsylvanicum; the stink-pot mud terra- pin or Musk Turtle, C. Odoratum; and the blood-stained mud terrapin, C. Cruentatum. The two former are distributed throughout the Eastern State of North America, while the latter is confined to Central America.
In C. Pennsylvanicum and C. Cruentatum, the plastial lobes are freely movable; the plastron, however, in the former species, is small, and consequently does not close up com- pletely against the rim of the carapace, as in the case of the latter. The end of the tail is provided with a horny, nail- like appendage in both sexes in C. Pennsylvanicum, it is pres- ent only in the female in C. Cruentatum, and is absent in both sexes in C. Odoratum. In the latter species the plastron is considerably narrower and smaller than in the two pre- ceding, and the lobes are only feebly movable. This terra- pin derives its name from the fact that on being alarmed it emits from certain glands a remarkably pungent and most disagreeable odor of musk.
VENTRAL VIEW OF A LEATHER BACK TURTLE
The members of this family, none of which exceed a shell length of six inches, are found in muddy ponds or ditches, feeding on small fish and tadpoles. They are said to be very treacherous creatures ; when handled they immediately with- draw into their shells, firmly closing them ; they do not re- main inside for long, however, for after a few seconds they dart out with unexpected rapidity, their mouths wide open, ready to inflict a severe bite with their cutting jaws. The back of the legs of the male in some of the species bears two patches of horny tubercles, and 'by rubbing these against one another stridulating sounds are produced very similar to those made by grasshoppers.
The widely distributed family Testudinidae, which embraces some 130 species, includes a number of strictly aquatic gen-
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THE SNAPPING TURTLE NOTED FOR ITS SAVAGE DISPOSITION. THE VENTRAL VIEW SHOWS THE SMALL
CROSS-SHAPED PLASTRON
era, as well as all the land tortoises, the passage from one form to the other being so gradual as to preclude any sharp definition. With the exception of Australia and Papussia, its representatives are distributed throughout the greater part of the world.
Batagur and Hardella are two closely related aquatic gen- era, represented each by a single species ; the former, inhabit- ing Bengal, Burma, Siam, and the Malay Peninsula, is to be distinguished from the latter, which is confined to northern India, by the fact that its front limbs have only four claws, instead of the usual five. The limbs are very broadly webbed, somewhat approaching the paddle-shape. The tail is short.
The Baska Turtle, Batagur baska, abounds in the Ganges and its tributaries, and is occasionally caught out at sea in fishing nets. Although purely a vegetable feeder in its native waters, specimens in the London Zoo all develop a taste, we are told, for the bread, biscuits, and buns thrown into their tank by visitors. The eggs of this species, the collecting of which is a royal prerogative in Siam, resemble hens' eggs in size and shape.
Hardella thurgi, which likewise feeds solely on aquatic plants, is, according to Anderson, brought to Calcutta in large numbers during the cold months and sold to a low caste of Hindoos, who keep them alive in tanks, selling and eating them themselves. He gives the following account of the ex- traordinary manner in which they are captured : "A number of men, all but naked, collect together, each man being pro- vided with a large bundle of green marsh grass neatly tied up in the form of a cylinder, measuring about two feet long. These men enter the water, throwing the bundles before them, which act as floats, and on which each man rests his chest as he gets beyond his depth. Then, one after another, they push away these floats, dive to the bottom of the river, and reappear generally with an example of Hardella obtained in the mud."
Chryseviys is a large genus distributed throughout North and Central America. The carapace is feebly convex, the plastron is immovable. Although eminently aquatic, frequenting rivers and ponds, and ditches in the case of C. picta, the painted terrapin, these terrapins often leave the water, and are most active on land. The soft parts as well as the shells are in most species most beautifully marked. In C. ornata, for instance, the head and neck are streaked with orange, while each costal and marginal shield is provided with a large yellow or orange ocellar spot. These markings are brighter and much better defined in the young than in the adult, where, in a good many cases, they disappear almost entirely. In C. scripta the sides of the head are ornamented with bright yel- low, or yellow and pink bands. Mr. Hugh Smith has given an interesting account of the breeding habits of this species. The egg-laying season, it appears, is in June and July, and the eggs are laid in some cultivated tract, usually a cornfield
adjoining water, the nests being made some distance away from the water, sometimes more than a hundred feet. The nest, which is shaped like a bottle, is made usualy in a sandy clay, above high-water mark, the hole being dug out by the female with her fore-legs. The size of the nest depends on the size of the animal, an average nest being four inches deep and four inches wide. The eggs, up to thirty-five in number, are laid at one time, and when the laying is com- pleted, earth is scraped into and over the hole and packed lightly. The packing is accomplished by the terrapin's raising herself as high as possible on her hind legs, and then dropping heavily. As soon as the nest is covered over the terrapin withdraws to the water. If a terrapin is disturbed while making a nest or laying, she will abandon the nest. The young hatch in the autumn, but remain in the nest, where they hibernate until the following spring. On emerging they are about the size of a fifty-cent piece. This terrapin form- erly supported a profitable fishing industry, but of late years nas become rather scarce, those caught being accidentally taken in fishing nets.
The European pond tortoise, Emys orbicularis, is distributed throughout the greater part of southern Europe, Algeria, Tunisia, and southwest Asia. In Central Europe it extends locally as far north as Central France, Holland, Prussian, and Poland. The coloration of the shell is subject to much variation ; it is usually dark brown or black with numerous yellow radiating lines, or spots ; the plastron is yellow and brown, occasionally entirely blackish brown. The head is black, with lighter dots, which are usually yellow, and in some males of a pale brown. The shell, which is oval in the adult, round in the young, is smooth, with a few well-marked ridges on each shield. The tail is as long as the shell in the quite young, two-thirds that length in adult males, and about one- half in the females.
The tortoise generally hibernates in the mud at the bot- tom of the pond or river towards the end of October. The lethargy, especially of those hibernating in shallow waters, is not very profound, and a little sunshine, even in mid-winter, is sufficient to awaken them from their slumbers. They re- sume their activity towards the middle of March, pairing in April, and laying up to a dozen oblong eggs in May or June. Adult specimens do well in captivity ; they feed both on land and in the water, usually upon meat or fish, but will sometimes eat lettuce. The quite young are, however, exceedingly deli- cate, and generally succumb to pneumonia after a few months of captivity. The flesh of this species is said to be moderately good eating, and was formerly appreciated as a delicacy for "fish days" in the Bomian Catholic parts of Germany.
Blanding's terrapin, Emys blandingi, is a North American species, closely resembling the European pond terrapin. The carapace, which is slightly more convex than in the latter species, is jet black, spotted with bright yellow. The plastron
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is yellow and black. The head is brown above, yellow beneath. Like its European ally it is easily domesticated. It takes to land frequently in search of a change of diet, feeding on in- sects and berries.
In Clemmys the plastron is united to the carapace by bone and not by ligament as in Emys, from which it does not other- wise differ. The genus is represented in Europe, Africa, southwestern Asia, China, Japan, and North America. Two species are found in Europe, the Iberian terrapin, CI. leprosa, which inhabits the Spanish Peninsula, Morocco, Algeria, and
PAINTED TURTLE IN AN AQUARIUM
Tunisia, and the Caspian terrapin CI. caspica, restricted to southeastern Europe and Asia, from the borders of the Cas- pian Sea to the Persian Gulf.
In CI. leprosa the carapace is dark olive; the plastron yellow. The head is olive, the sides being streaked with yel- low, while an orange spot is situated between the obit and the ear. A number of yellow bands extend along each side of the neck. The shell seldom exceeds six inches in length. Its specific name is derived from the fact that the creature is subject to a gangrenous disease, when living in not suffi- ciently aerated waters, which gives the shell a leprous ap- pearance.
CI. caspica is more handsome, the carapace being elegantly marked with black-edged yellow, wavy markings. This and the preceding species are far more aquatic in their habits than Emys orbicularis, and, unlike the latter terrapin, never feed out of water. Freshly captured specimens of the Caspian ter- rapin emit, when handled, a disagreeable odor, which is due, as in Cinosternum, to the secretion of a pair of inguinal glands. When kept for some time in confinement, however, they lose this objectionable habit. Although reaching a length of about five inches, imported specimens rarely measure more than two, and, like most young terrapins, seldom thrive for any considerable time under captive conditions.
In Cistudo, the representatives of which are the true Box Tortoises, the plastron is connected with the carapace simply by ligaments, and is divided into two movable lobes, enabling the creature, after withdrawing its head, neck, limbs, and tail into the shell, to close it hermetically like a box. The digits are almost entirely free, being provided at most, with only a very short web.
With the genus Cinixys begins the series of entirely terres- trial types, the true tortoises, which are provided with club- shaped feet and webless digits, and in which the plastron is always united to the carapace by a broad bridge.
In this genus a remarkable modification of the shell takes place, the posterior portion of the dorsal buckler being hinged and movable.
The Gopher Tortoise, T. polyphemus, of Florida, is remark- able inasmuch as it lives in burrows, which it only leaves on
very hot days. The burrows are excavated in the sandy soil by means of its front limbs, which are armed with abnormally long claws, with the help of the plastron, which is provided with a small spade-like projection. According to H. J. Hub- bard the galleries descend at an angle of 35 degrees, and reach a vertical depth of about nine feet from the surface of the ground, measuring often as much as eighteen feet in length. The temperature at the lower end does not vary much through- out the year, not falling below 70 degrees F. in winter nor rising above 80 degrees in the summer. Once the tortoise has established itself in one of these burrows, it cannot be made to vacate or excavate a new home, but settles down for long periods, some of the burrows being known to have been in- habited by the same individual for as much as twenty-five years. The galleries, if abandoned, immediately become filled up with the shifting sand ; they afford a refuge for various other animals, including opossums, raccoons, and owls. The Gopher Tortoise does not survive many months of captivity, making no attempt to burrow.
The Elephantine Tortoise, T. elephantina, is now nearing extinction in its native home, Aldabra, but of late years it has been introduced in the Seychelles, where it is now fortunately thriving under Government protection. The shell of large specimens measures five feet in length.
The South Albermarle, T. vincina, grows to an even larger size, its shell reaching over five and a half feet in length, such specimens weighing at least five, hundred pounds. It may be distinguished from T. elephantina by the absence of the nuchal shield.
Some interesting notes have recently been published by the Governor of the Seychelles regarding the conservation of land tortoises in the island. The largest specimen of the herd measures four feet nine inches over the surface of the cara- pace, and is probably the largest living specimen at the pres-
A PAIR OP LOGGERHEAD TURTLES DISTINGUISHED FOR THEIR LARGE HEADS
ent day. "Gordon," as the cretaure is called, shows likes and dislikes, and is very combative, having bitten many visitors who presumed on his apparent lethargy. The breeding sea- son in the Seychelles extends from January to April, when the females lay their eggs in holes dug out by their hind limbs, and then covered over. The eggs, which are white, round, and the size of a tennis ball, vary in number from nine to twenty- five. The young hatch out in from 120 to 130 days, and work their way out of the ground ; half the eggs are usually infertile, but in some years of great drought very few young appear, being apparently unable to reach the surface. Their rate of growth is exceedingly fast, since they measure, when four years old, nearly two feet in length. When twenty-five they are said to attain full growth.
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These tortoises in the London Zoological Garden hibernate from the end of October to the beginning of March. They are fed chiefly on cabbage, of which they consume, during the hot weather, almost a bushel a week each. "One large Ele- phantine Tortoise is peculiarly untortoiselike in his taste, being extremely fond of the bread and buns which he receives from the visitors, whom, if provided with these dainties, he will follow round his enclosure, often attracting their atten- tion by butting against the railing of his paddock."
The Green Turtle, Chelone mydas, enjoys world-wide fame, for it is from the flesh of this creature that the famous "turtle soup" is obtained. The heart-shaped shell is smooth, polished, and slightly notched and serrated behind. The head is large, somewhat compressed at the sides. The jaws are provided with very much serrated cutting edges at the sides, the lower beeing hooked in front. The shell attains a length of about four feet, such specimens weighing about four hundred pounds. Al- though fairly abundant in all the tropical seas, the great bulk of those received in this country are obtained from the West Indies.
"The eggs are deposited on the sandy shores of uninhabited islands. Before embarking on her parental duties, the female makes a thorough inspection of the beach where she has the intention of laying. Satisfied that the situation is appropriate, she digs a hole nearly three feet deep, with her flippers, and therein deposits some two hundred eggs. These holes are then covered over with sand and levelled down by means of the flippers, in such a manner that it is only with the greatest difficulty that their place of concealment can be discovered. The whole operation of digging, laying, and filling up lasts about a couple of hours, when the turtle once more returns to the sea, leaving the eggs to be hatched by the heat of the sun." After a few weeks the young turtles break through their egg-shells, lift up the sand, and, without the slightest hesitation, make straight for the sea. Although man is per- haps their chief enemy, enormous quantities of young turtles are devoured by large fish, and only a very small percentage reach maturity.
The food of the Green Turtle consists almost entirely of fish and marine plants.
The Hawksbill Turtle, Chelone imbricata, also a powerful swimmer, inhabiting all the tropical and subtropical seas, only coming to shore at the breeding season, derives its Eng- lish name from its prolonged hooked snout. The carapace, the shields of which are more or less imbricate, is marbled yellow and dark brown. It is a somewhat smaller species than the Green Turtle, the shell of adult specimens rarely measuring more than three feet in length.
Although not edible, this animal is highly esteemed on ac- count of its horny shields affording the substance known as "tortoise-shell." According to Sir Edward Tennant, the cruel method is employed in Ceylon of suspending the living turtle over fires, until the heat detaches the plates -from the bones of the carapace, after which the creature is put back in the water, it being erroneously believed to return again with a regenerated shell. It appears that if the latter be removed after death the color becomes cloudy and milky, and therefore useless from a commercial point of view.
An interesting account of the fishery resources of the Philip- pine Islands, which contains some interesting information on this turtle, has been given recently by Mr. Alvin Seale. Dur- ing the year 1909, there were exported from the Philippines 2,040 kilograms of tortoise-shell. While a small number of turtles are caught with hook, net, spear, or trap, by far the greater number are captured when they come to shore in order to deposit their eggs, the animals being killed without being given a chance to lay, a short-sighted policy, which, unless the turtles are protected during the breeding season, which is from May to August, will eventually result in the destruction of the fisheries.
In the Philippine Islands, it is satisfactory to learn that the method of removing the tortoise-shell from the animal's
back, described by Tennant, is not resorted to, the shell in most of the islands being removed after the turtle has been killed, by immersing the carapace In boiling water until the shields loosen ; another method is to bury the body in the sand for about a week, when the shields become detached. The quantity of tortoise-shell obtained from a single adult specimen varies in weight from five to ten pounds.
The Loggerhead Turtle, Thalassochelys caretta, is character- ized by an enormous head. The carapace, which is very strongly arched, is uniform dark brown or black. The lower jaw is slightly hooked. Its range is even wider than that of either the Green or the Hawksbill Turtle, it being found much farther north, and being in fact not uncommon in the Medi- terranean and neighboring parts of the Atlantic. It is of little value from a commercial point of view, its flesh, although not absolutely inedible, being far inferior to that of the Green Turtle.
Although in fresh water aquariums all these marine forms refuse to feed, and die of starvation in a very short time, they will live for many years under captive conditions if pro- vided with sea-water, even in quite small tanks.
As we have said, the flesh of the loggerhead turtle is not very edible. However, the eggs laid by these animals are not only edible but very delicious. The writer has often gathered them on the coast of Florida, fresh from the nests. They are perfectly spherical, creamy white in color, and the "shell" in- stead of being brittle like bird's shell, resembles tough parch- ment in look and feel. The eggs are never eaten simply boiled so far as I know; the reason given being that the albumen does not solidify. This fact, however, I cannot vouch for personally, but I have eaten dozens of these eggs in the form of griddle cakes, puddings, etc. They are entirely free from any fishy or unpleasant taste or odor and are very nutritious. They are not only popular as an article of food among the natives of Florida, but they are also keenly enjoyed by various wild animals, including bears, opossums and skunks. So keen is the competition for these delicacies in fact, that one must make a very early start to obtain the prize.
When ready to deposit her precious burden the female turtle swims ashore at high tide and crawls straight up the sandy beach for a distance of several yards, where the nest will presumably be safe from the waves. She then excavates a hole, usually about a foot in diameter and perhaps IS inches deep. In this a large number of eggs is deposited, usually ranging from 120 to 150 eggs. As will be seen such a nest is a find indeed, comprising several pounds of valuable food ; consequently people living near the coast often make up "turtle egging parties" during the spring and summer months when the tide is right, in the hope of coming upon one or two turtle "crawls." The crawl consists of the parallel marks left by the creature's flippers as she toils her way across the sand. After depositing the eggs she fills the hole neatly, and then apparently whirls round and round. Consequently, at the end of each crawl, there is a sort of roughly circular whorl in the sand. The pocket of eggs, however, is by no means exactly in the center of this whorl, so that it requires considerable skill to locate it when digging up the whole area. Experienced hunters judge its location by the greater softness of the sand. I well remember, some years ago, walking up the Ormond Beach before that part of the world was as fashion- able and as much frequented as at present — for two or three miles and finding several crawls, but in each case the nest was completely empty, the reason being very evident from the fresh bear tracks which led the way. Finally we came in sight of the bear himself and turned back, though he was undoubtedly in a very amiable frame of mind after just swal- lowing hundreds of the titbits Ave ourselves coveted.
Since the mother turtle never returns to look after her off- spring, once having prepared for their proper launching into the world, many of them are devoured at a tender age, even when they have escaped being eaten in the form of eggs. There undoubtedly should be some sort of legislation to protect these
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creatures, and it would be well to require the finders of the eggs to rebury a certain percentage of thern in a fresh place where there are no tell-tale signs to reveal their presence. I have done this myself and been rewarded by the entertain- ing spectacle described above of the baby turtles scrambling out of their little nests and setting solemnly off for their first dip in the chilly waters of the ocean.
HOW SPRING FLOWERS CAN BLOOM UNHARMED IN SPITE OF FROSTS.
In studying the phenomenon of the chilliness of the ground during the night as a result of spring frosts, observers have usually confined themselves to recording the temperature observed immediately above the vegetation, woods, grass, herbs, etc., which usually covers the ground, but a Scotch in- vestigator, Mr. T. B. Franklin, has recently attacked the prob- lem in a much more thoroughgoing manner, basing his studies upon the assumption — which he has proved to be correct — that there is frequently a very great difference between the temperature of the ground itself and that of the air above it. This difference is chiefly due to the nature of the protective layer above the earth itself.
The cooling of the ground on a clear night is due to radia- tion, but the' effects produced by this are at first counter- balanced by the conduction of heat, which brings toward the surface of the ground the warmth of the deeper strata. Thus when the earth begins to freeze the latent heat liberated by the freezing of the moisture must be radiated before a new fall in the temperature of the ground can occur. In other words, it is only the surplus of the radiation after the balancing of these two factors which is effective in lowering the temperature of the ground. Accordingly when the surface of the ground is dry and the conductivity is reduced, or when the temperature of the deep lying strata is already low, the ground is cooled much more rapidly by radiation.
It is obvious, therefore, that the temperature of the surface of the ground depends upon three factors :
1. The comparative humidity of the air.
2. The degree of dryness of the superficial layers.
3. The temperature of the subadjacent layers.
Mr. Franklin undertook to determine the comparative im- portance of these different factors. In order to calculate the power of conduction he measured the temperature at the sur- face at a depth of 10 cm. Between these two points the temperature usually is almost uniform so long as the surface does not freeze.
The results obtained admirably proved the correctness of the theory, but it was found that on clear, calm nights, when the stars of the fifth magnitude are visible the radiation of the ground depends upon the relative humidity, other factors such as condensation and evaporation, exerting but little effect upon ground temperature. The temperature of the surface tends to fall rapidly below the temperature at a depth of 10cm., by a number of degrees such that the conduction starting at this depth exactly balances the radiation. After this balance has been attained, the surface temperature cannot fall more rapidly than that of the stratum at a depth of 10cm., and consequently when there is a sufficiently high temperature of the subsoil frost is improbable. The difference of tempera- ture between the surface and the depth of 10 cm., which would constitute an equilibrium between conduction and radiation is probably about 5.5 °C.
3. In winter, at which time the ground is almost invariably humid, it possesses a uniform maximum conductivity, but it may rise to 11 degrees cent., after a dry period in the spring, or at the beginning of summer. These data seem to indicate that it will be possible in practise to predict a frost at night according to observations made in the afternoon with regard to the three factors mentioned ahove.
When the ground is covered with any substance which is a poor conductor of heat, radiation from the surface is con-
siderably diminished on clear nights. Mr. Franklin made a series of observations concerning the minimum temperature of the surface of the ground when entirely bare and when covered with layers of different substances. These layers were each 12.5 mm. in thickness and consisted of well-crumbled, loose earth, of cinders, of manure, of dead leaves, and finally of a natural growth of grass and moss. The maximum thermic efficiency of these five protective layers was as follows :
1. Crumbly earth, 1.7CC.
2. Ashes, 3.3°C.
3. Manure, 3.6°C.
4. Dead leaves, 4°C.
5. Natural grass and moss, 5.5°C.
During the winter of 1918-19, when these experiments were made it was found that the ground covered with either grass or moss never froze.
By covering the ground with a layer of ashes and placing a screen on top, Mr. Franklin succeeded in maintaining the tem- perature at 5.5°C. above that of the naked ground, thus equaling but not exceeding the protective effect of the natural covering of grass or moss.
On the slopes of ditches, or in the shelter of hedges and woods protected against the wind and against the effects of radiation by a layer of dead leaves, of grass, or of moss, it will be readily seen how the roots of spring flowers can thus pass through winter without being touched by frost. Even in December, when there is a period of warm rain to give the necessary heat to the ground, these plants will begin to send up their leaves and may be seen blooming at times, just when the winter is most severe. Thus Mr. Franklin saw a primrose which had been so stimulated by the .mild weather of Decem- ber, 1918, that it had made its way through the mossy turf above it and bloomed February 10, 1919. The leaves and flowers in the air, had at this time a temperature of 9.5°C. below zero, while its roots safely buried in the warm earth were 0.5 °C. above zero. Thus there was a difference of not less than 10°C. between the roots and the flowers.
VOLUNTARY DETERMINATION OF SEX BY MEANS OF CHEMICALS.
During the last five years certain experiments with respect to the determination of sex have been conducted in the Phar- macological Institute of the University of Frankfurt. The results obtained were eminently successful and were recently described by Dr. L. Adler, at a session of the Frankfurt Senckenberg Society. The investigator, Richard Hertwig, and his students are able to produce males from frogs, common brown frogs (Rana fused), during the period , of development by the application of heat of from 25 to 28 degrees cent. Un- der these conditions certain transformations take place. The same success was obtained by the use of eggs which have at- tained a state of hyper-maturity before being fertilized. Dr. Adler also discovered that the male frogs produced from such eggs exhibit transformations of the thyroid gland in a very high degree, and these largely correspond to the alterations observed in human beings occasioned by Basedow's disease. Another investigator, Gudernatsch, succeeded in obtaining 100 per cent of male frogs by feeding tadpoles with the substance of the thyroid gland. In fact, among 400 tadpoles thus fed there was not a single female.
Under the influence of heat a retrogression or degeneration of the thyroid gland occurs and by reason of this some of the effective substance contained by this gland is liberated and thereupon occasions the transformation of female organs into male organs. The chemical agent concerned in this reaction is iodide of albumen. Very curiously the males thus artifi- cially produced all had uncommonly small weak legs.
Some experiments have been made with animals higher in the scale, but so far as the writer knows without much suc- cess. It must be remembered, too, that there is more or less danger connected with the use of the thyroid treatment.
Microscopic Water Contaminators*
Minute Organisms That Give Unpleasant Flavors and Odors to the Water Supply
By Morton Charles Kahn
Department of Hygiene, Cornell University Medical College
WE have all, at one time or another, encountered for- eign flavors and odors in the water supply, both agreeable and repugnant. For the most part these are due to the presence and growth of microscopical plants and animals. Such effects, together with the presence of tur- bidity and color, are always looked upon with suspicion by the public, for there is nothing to which a community is more sensitive than something unusual in its drinking water or in its household supply, be it detectable by smell, sight, or taste.
Large and small flowering plants, commonly found in res- ervoirs and along sources of water supply, such as pickerel weed (Pontederia) , water plantain (Alisma), eelgrass (Vallis- neria), and many others, rarely cause trouble. While they may be a nuisance in a mechanical way, due to their abun- dance, or even by contamination since they furnish a place of rest for the more obnoxious forms, still in themselves they are harmless, and produce no direct effect upon water used for domestic purposes. It may be said that although a large ac- cumulation of these plants undergoing the processes of decay, together with other decomposing organic matter, may produce unpleasant flavors and odors, this condition seldom occurs and if it does it is a comparatively easy task to rid a water sup- ply of this trouble.
There remains one group of plants, the algae, mainly micro- scopic, which is unfamiliar to most people and much too often neglected because it seems to possess no economic importance. This is a mistake, for these microscopical plants have a real influence on the general public welfare, in that they are direct causative agents for practically all of the bad odors and flavors in drinking water and, besides the bacteria and a few proto- zoans, are the only organisms which need be taken into ac-
*Reprinted from Natural History, January-February, 1920.
count when considering the biology of drinking water from a hygienic standpoint. Some of the algae may be seen with the naked eye, that is of course when they occur in vast num- bers so as to form a scum on the water's surface. Most of them may be seen only with a microscope, and it is only by the aid of this powerful magnifying instrument that any of their individual structures can be studied. Their structure, too, for the most part, is very beautiful, forming one of the most fascinating fields of microscopy.
Let us first consider the diatoms, a great group of trouble- makers belonging to the algae. It is known that some of them give rise to serious trouble in the water supply.
Water inhabited by excessive numbers of these organisms most frequently develops a very disagreeable fishy odor. Some people think the odor like that of geraniums. Personally, however, I think it far less agreeable than the. fragrance of this common garden flower. The specific types of diatoms which cause the disagreeable conditions are : Asterionella, respon- sible for the distinct fishy smell, and Tabellaria, Meridion, and Diatoma, when they become numerous. When sparse, on the other hand, they are possessed of a distinct aromatic principle, which is not considered disagreeable. Diatoms are exceedingly troublesome when contained in water used for laundry purposes, or for the manufacture of paper. This is due to the fact that they contain a greenish pigment, which stains articles coming in contact with it.
Structurally a diatom is very beautiful. It may be de- scribed as resembling a glass box made up of two halves, one fitting tightly within the other, the walls being strongly sili- cified. Diatoms are not without their redeeming features, for it is this silica contained in diatomaceous earth that makes it valuable as a polishing powder. Earth containing diatomous
HWrvS
SOME INTERESTING MICROSCOPIC CONTAMINATORS OF PUBLIC WATER SUPPLY The Uroglena (center illustration), which are claimed alike by botanists and zoologists, grow in colonies, single-celled bodies embedded in the surface of a gelatinous sphere. Only the slightest pressure is required to .break the delicate structure, liberating an oil with a fishy odor. The other forms in the illustration are Synura anid Syncrypta. Bad odors, especially cucumber odors, have in the past been traced to Synura. Even so few as five or ten colonies to a cubic centimeter will cause a perceptible odor.
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MICROSCOPIC DIATOMS WHICH CAUSE DISAGREEABLE ODORS IN DRINKING WATER Seen under a microscope, a diatom is geometrical in design, with two transparent valves, fitting one into the other like a shallow glass box and its cover. The valves are variously marked with points or grooves so minute that from several hundred to several thousand occupy a millimeter. These imcrease the friction of the diatom with the water and tend to prevent it from sinking — for a diatom is heavier than water, yet must float near enough to the surface to get sunlight for growth. The illustrations show common diatoms in both valve and face views; 3 and 4 (at the left) are Asterionella which may give a fishy odor to. water; 6 illustrates the rapid multi- plication of Asterionella by division. It is said there are nearly 10,000 species. Some species have a spring and fall period of maximum growth, such are Synedra (8-11), and in the illustration at the right Diatoma (1-3) and Taoellaria (6-9).
remnants is used to some extent in the manufacture of dyna- mite. Diatom shells form no mean portion of certain of our well-known brands of tooth powder, and last, but by no means least, the living marine types form an important part of the diet of some of our food fishes.
The methods used for multiplication by these members of the Diatomacese, are unlike anything of a similar nature found elsewhere among the alga?. The two valves or halves of the organism begin a slight process of separation, and as the con- tents divide into two parts, there are formed within two new halves, one fitting into the larger half of the original cell, and the other forming a new box within the smaller half of the parent cell. These then separate, forming exact counter- parts of the mother cell, although one is a trifle smaller than the other. In addition to the above mentioned method of reproduction, the plant also possesses the power to form a large spore, making it more or less resistant to adverse condi- tions ; also, it has been noted that the diatom cell may break up into a number of much smaller spores, each one capable of developing into a new plant.
One organism claimed alike by botanist and zoologist, but at any rate a troublemaker for the hygienist, is Uroglena, belonging to a group known botanically as Syngeneticeae. This form demands especial attention, for it is probably respon- sible for more trouble in the water supply than any single
representative of the various groups of microscopical plants, excluding of course the pathogenic bacteria.
Uroglena is widely distributed over the United States, but is more frequently encountered in New England and in some of our middle western states, Indiana, Ohio, and others. Uro- glena lives in colonies in appearance resembling a colorless sphere, with a large number of greenish cells embedded in the periphery. Usually much smaller than one-half a millimeter in diameter, the Uroglena colony may, however, attain that size. Each individual cell is equipped with a pair of cilia of un- equal length, and it is by vibration of these hairlike append- ages that the colony is propelled through the water. Each cell of the colony contains in addition to a well-defined nu- cleus, .which appears as a red spot, a single greenish colored body, and several vacuoles. By far the most important con- tent of the cell from a sanitary standpoint and the one that causes the organism to be feared by those responsible for the water supply, is the large number of oil globules. It is the liberation of this oil that causes all of the trouble, namely, the detested fishy-oily odor usually attributed to water con- taining this form of life. The oil seems to be held in rather loose combination, so that the mechanical breaking of the colony serves to liberate it in sufficient quantity grossly to contaminate the water. The cells of Uroglena are, unfortu- nately, very fragile, and much force is not required to rupture
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SCIENTIFIC AMERICAN MONTHLY
July, 1920
MINUTE WATER PLANTS THAT CONSTITUTE THE COMMON BRIGHT G-REEN SCUM OP OUR PONDS The many-celled Spirogyra, with its beautiful spiral fronds, is shown in 4, at the left, also in 5 after the formation of zygospores, each made by union of the cell contents of adjoining filaments. Other filamentus algae which have natural odors and may be sources of disturbance in reservoirs of water supply, are (at the left) Hyalotheca (1), Zygnema (6), Taucheria (7), Conferva (8), Cladophora (9). The Tolvox (at the right, 3), consists of a gelatinous sphere often one millimeter in diameter in which the several thousand microscopical cells (black dots in the drawing) are embedded, with their cilia pointing outward. By the beat of this multitude of cilia the sphere, which is lighter than water, is kept rotating ancl moving about independently like an animal. This form contributes a strong fishy odor and must be filtrated from the water supply. Such forms as Eudorina (4) aad Pandorina (5) also may give a fishy odor to the water.
them and liberate the oil. Usually mere pumping, or even the force of gravity through pipe lines necessary to distribute the water, is enough to cause the disturbance. The exact na- ture of the oil is not very well understood. It is believed that it is not unlike the so-called essential oils, being nonvolatile at the temperature of boiling water, and seeming to resemble the oils obtained from some of the diatoms and blue-green algae. The methods of cell division in Uroglena are somewhat pecu- liar and decidedly interesting. Before dividing, the cell seems to turn in the periphery of the hollow gelatinous sphere, until it is at right angles to the position usually occupied. Then at the end of the cell which originally pointed toward the center of the sphere, there is formed a pair of cilia similar to those at the opposite pole, and the appearance of the charac- teristic spots of red is then noticed. The cell begins to be sharply constricted, and as it gradually divides, the two halves are drawn back through *an angle of about 45 degrees, so that when the cells are finally formed, they occupy a posi- tion similar to the one normally assumed by the parent. When a cell colony becomes too large, it divides into individual cells, and these by numerous processes of division soon grow into new spheres. In addition Uroglena is also able to form spores, so that it is quite ready to survive periods that would normally lead to its extermination or at any rate seriously handicap its multiplication. Queerly enough, Uroglena seems
to thrive best during the cold winter months, especially when the surface of the water is frozen. In Europe just the reverse is true, July and August are the months most favorable to its growth, and it disappears altogether at the approach of cold weather. For this reason many seem to think that the European and American types are different species.
Other Syngeneticese are concerned with the contamination of water, but usually not to the same extent. Synura and Syncryta are both accused of having a bad effect, Synura being responsible for the offensive "ripe cucumber" odor formerly thought to be caused by fresh-water sponges.
Without doubt Uvella should be spoken of, as it is one of our most dreaded forms, and to it has been reputed the cause of an acid in the water which is most disagreeable. It greatly resembles Synura and many believe it to be the same organ- ism ; it differs, however, from that form in the lack of a sepa- rate investing membrane, and by the posterior location of the contractile vacuole. There are also few zooids contained in the cluster.
Another very bothersome water microorganism, which may be the cause of much annoyance, is the common Spirogyra, which has been known to cause thousands of dollars' worth of damage by smothering growing water cress in artificial beds constructed for the winter propagation of this salad plant. When the cress is cut for market, the mutilation leaves the
July, 1920
SCIENTIFIC AMERICAN MONTHLY
31
plant in a much weakened condition, and if Spirogyra gets a start, it forms a thick mat over the surface of the water, pre- venting the growth of the cress, and often killing the entire crop in a given district.
Anaboena, one of our most important water contaminants belonging to the order Nematogenae, surely merits more than a passing mention. George Chandler Whipple, professor of sanitary engineering in Harvard University, in a graphic description of the serious amount of trouble this form may cause, tells how the large Chestnut Hill Reservoir, Boston, was contaminated by Anaboena. This blue-green algal form multiplied to such an extent that in the course of a compara- tively short time it polluted the entire line of supply of the communities getting their water from the above-mentioned
EUGLENA, A MINUTE FR.EE-1SWrM1M.lNO ORGAN- ISM WITH A FLEXIBLE WHUPLIKE FLAGELILUM NEAR THE MOUTH Immense numbers of Eug- lena may collect in a green or reddish scum on quiet water.
STENTOR, AN INTERESTING MI- CRO-ORGANISM WHICH NEVER EXISTS IN SUFFICIENT NUMBERS TO BECOME A PEST Rapidly vibrating cilia at the top where the mouth is, maintain a cur- rent which carries in food particles.
GLENODINIUM WHICH GIVES A FISHY ODOR It is said that Glenodmium imparts a fishy odor to water in which it grows, hut the species is not common enough to he an important source of trouble. In gelatinous masses on the water it shows phos- phorescence.
source. In structure and form Anaboena much resembles an irregular chain of green beads. The vegetative cells are from five to twelve microns in diameter, depending on the species. It possesses both spores and peculiar dead cells called hetero- cysts. Being a most abundant producer of obnoxious oils, it causes annoyance in much the same way as does Uroglena. Among other forms giving rise to unpleasant odors and
flavors are Dlnobryon, Bursaria, Peridinium, and Glenodinium. They are not often causes of bother, and are interesting for the most part because of their unusual structure, and like many other microorganisms show the varied forms of plant and ani- mal life which may exist in a given source of water used for domestic purposes.
To Dr. G. T. Moore, head of the Department of Botany, Marine Biological Laboratory, Woods Hole, and Mr. K. F. Kellerman, associate chief of the Bureau of Plant Industry, Washington, D. C, two of our most efficient experts on water biology, belongs the credit for suggesting a very good means of controlling these minute pests. The method consists of us- ing small amounts of copper sulphate, a chemical which seems to have a specific toxicity for the lower forms of life. The
PERIDINIUM WHICH GIVES A "CLAM SHELL" ODOR Peridinium is a consort of the diatoms in the floating life of lakes and reservoirs and especially of the sea. It is not sufficiently abundant to be troublesome in the water supply, but it is said that it produces a fishy odor "like that of clam shells."
COLONY OF DINOBRYON WHICH GIVES A FISHY ODOR. These colonies may be either attached to objects in the water or free-swimming. New colonies are formed and dispersed by spores so that large numbers of the animalcules may be generated within a brief period if conditions are favorable.
requisite amount of copper sulphate is placed in a sack of coarse cloth, and drawn slowly back and forth over the sur- face of the water in the reservoir. Diffusion and the natural circulation of the water serve to mix the chemical and dis- tribute it to all parts necessary. According to Professor Whipple the amount of copper sulphate to be used varies with the following factors : 1, organisms present ; 2, temperature of
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SCIENTIFIC AMERICAN MONTHLY
July, 1920
the water ; 3, the amount of dissolved organic matter ; 4, hard- ness of the water. In the case of the more susceptible or- ganisms such as Uroglena and Anaboena, dilutions of one part copper sulphate to five to twenty million parts of water is sufficient, while for the more resistant forms such as the dia- toms, the amount required to produce a lethal effect on the species may be as great as one part of the chemical to one million parts of water. Fortunately, the organisms giving the greatest trouble are the ones which most easily succumb to the copper sulphate method of treatment.
Objections have been raised against this method, due to the poisonous nature of the substances used as an algsecide. There is little reason to believe that there is much to be feared, how- ever, considering the high dilution of the chemical when it ultimately reaches the consumer, especially when the use of copper sulphate is followed by filtration of the water, for by filtering the copper salt is largely removed. Much of the chemical is bound by the ever-present vegetation, while still another portion is precipitated. The use of the copper sulphate method of treatment is not advised, however, without expert supervision.
Pathogenic bacteria do not make the water unpalatable and thus are often tolerated in a water supply for a long time ; not until there has been an alarming increase in the death
rate from water-borne infections is their injurious presence brought home forcibly to the general public. With algse it is different, their presence for only a day or two will cause the water to become offensive to such an extent as to make the general rate of water consumption in the community fall far short of the amount needed for physical well-being. Even when a water supply is palatable in every way, people tend to drink far less than is normally needed. Just stop and consider what a vital substance water is : "Seventy per cent of our body weight is composed of it; it enters into the chem- ical composition of all of the tissues ; it forms the chief in- gredient of all fluids of the body and maintains their proper degree of dilution, and thus favors metabolism; by moistening various surfaces of the body, such as mucous and serous mem- branes, it prevents friction ; it furnishes in the blood and lymph a fluid medium by which food may be taken to remote parts of the body and waste material removed, thus promoting rapid tissue changes ; it serves as a distributer of body heat ; and it regulates the body temperature by the physical process of absorption and evaporation."
One of the most common dietetic faults is neglect to take enough water into the system. It is important, then, to have a pure and wholesome water supply that may be partaken of with enjoyment by all.
Theory and Practice of Lubrication*
Increasing the Life and Activity of Lubricating Oils by Means of the "Germ" Process By Henry M. Wells and James E. Southcombe, M.Sc.
THE considerations which we wish to bring forward in this paper are the results of many years' experience of the problems of lubricating oil and lubrication, studied from a physical and physico-chemical standpoint, as- sisted by an intimate and daily contact with the lubrication of all types of machinery and prime movers. Our primary object was to elucidate the reason for the obviously superior lubri- cating efficiency of fatty glycerides over "straight" mineral oils in a large number of practical cases which had come to our notice.
As a corollary to this we had to review the physical princi- ples upon which lubrication depends and to seek an explana- tion of the peculiar property which has been called "oiliness," "body," etc., by authorities in the past.
It may not be out of place here to review the position of our knowledge of lubricants and lubrication.
Professor C. V. Boys, in his Presidential address to the Physical Society in 1908, crystallized the position very happily in these words :
"It was found that the lubricating property of oil de- pended on something which at present is unknown. It is not viscosity — animal and vegetable oils lubricate better, i.e., they are more 'slippery' than mineral oils of the same viscosity, and though the oil trade has known how to make good 'slippery' mixtures, no one at present knows what 'oiliness' is, and this is at the present time an important physical quest of the engineer."
Again, Professor J. S. Brame has said that1 "the property of 'oiliness' was one of the most puzzling of the properties of oils. By some it was regarded as unnecessary to connect it with viscosity directly, since it was possessed in a much greater degree by some fixed oils than by many mineral oils which had practically the same viscosity."
It is necessary to distinguish clearly between two distinct classes of lubricating practice. On the one hand we have the lubrication of fast-moving shafts, etc., supplied with a large
*Paper read before the London Section of the Society of Chemical Industry, Feb. 2, 1920. Reprinted from the Journal of the Society of Chemical Industry, March 15, 1920.
V. Inst. Pet. Tech., 1918, 4, 219.
excess of oil frequently under pressure, and in this case the frictional values are dependent primarily upon the viscosity of the oil; the mathematical and experimental investigation of these cases have been amply treated by Reynolds, Tower, Lasche, and others. On the other hand we have to deal with slow speeds at high bearing-pressures, frequently with a very limited supply of oil, and it is in these cases that the special property of "oiliness" or "body" is requisite to maintain the film, and it is here that viscosity measurements no longer assist us in the choice of the lubricant.
This view received unanimous support at the recent dis- cussion on lubrication at the Physical Society.
What are the possible physical properties of a liquid which influence its character as a lubricant? They are viscosity, density, capillarity or surface tension, compressibility, and tensile strength. It is true that very little work has been done on compressibility and tensile strength, but from the ob- servations of Worthington and others it would appear doubtful
FIG. l FUG. 2
CAPILLARY ACTION OF MERCURY AS COMPARED WITH OIL
whether they would play a distinguishing role in the differen- tiation of oils ; and, further, as we shall point out, there is what appears to us an adequate explanation of the nature of oiliness without calling upon these properties.
So far as density is concerned there exists a wide range of petroleum mineral oils possessing specific gravities identical with those of the fatty or fixed oils, hence it is clear that density plays no determining part. Viscosity is, of course, of great significance in the cases of high speed, etc., just re- ferred to.
Now it remained for Ubbelohde to point out that only a liquid which "wets" or "spreads over" the solid can constitute a true lubricant, because in order for the liquid to force itself
July, 1920
SCIENTIFIC AMERICAN MONTHLY
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^* I- £
into the narrower spaces of higher pressure it is essential on capillary grounds that the said liquid shall "wet" the solid surfaces.
Consider the case of two eccentric glass surfaces which are being forced together with a drop of mercury or oil between them. Now since the mercury (Fig. 1) does not "wet" or spread over the glass, the meniscus in this case will be convex to the liquid, while in the case of the oil (Fig. 2), which wets the surface, the meniscus will be concave. In the case of Fig. 1 (mercury) the tendency on capillary grounds will be for the liquid to gather itself up into a drop and to pull the liquid film in the direction of a away from the narrower con- stricted area of greater pressure at b. In the case of oil (Fig. 2) the opposite will be the case. The oil will, owing to its meniscus, tend to be pulled towards b or, in other words, will force itself into the narrow spaces.
This is exactly what is required in a lubricant, namely, that it shall penetrate into the narrow spaces between journal and bearing, and from the above considerations one clearly sees that liquids which do not "wet" solid surfaces cannot be described as lubricants.
Only those liquids which "wet" a solid surface possess lubricating power in the generally accepted sense.
Although these considerations appeared to indicate the con- nection between lubrication and capillarity, it will be seen that they only go so far as to enable us to say that mercury is not a lubricant and that oil is a lubricant. This is a con- clusion of considerable theoretical interest, but it is not very
helpful to the oil technologist who A o desires to differentiate between
different classes of oils.
Accordingly we find that these speculations of Ubbelohde led to no practical result.
On the other hand, certain theo- retical considerations had led to the conclusion that the perma- nence of liquid films depended upon capillary relationships, and in particular that pure liquids would not form stable films. These H WATER principles had not been applied, \N-_-^/ however, to the problem of lubri-
cation, and, in fact, they were directly contradicted by prevail- ing practice in which there was a constant tendency towards greater purity, i.e., in the direction of refining the mineral oils which were used, and in the direction of using acid-free oil as a compounding ingredient.
The generally accepted view was therefore that capillarity was not a deciding factor in connection with the phenomenon of "oiliness," and various standard works contain statements to this effect.
It was under these conditions that we began our experiments. We were at once met by the fact that it was not possible1 to measure the surface tension between oil and the solid metal bearing, and it is probably on this account that Ubbelohde's speculations remained abortive. The usual "surface tension" is that of oil against air, and we confirmed the results of pre- vious investigators, viz., that the results so obtained, for in- stance, by observing the rise in a capillary tube, shed no light at all on the question under consideration.
At this point we decided to measure the surface tension of the oil against an immiscible liquid in the hope that this might furnish some criterion of "oiliness." On proceeding to measure this interfacial tension, i.e., the surface tension be- tween oil and water, startling results were at once obtained. The method of experiment was by the drop pipette as follows : The pipette consists of a U-shaped capillary tube provided with a bulb A (Fig. 3) and a ground glass orifice B. The bulb A is filled with oil to the mark E. By means of the
FIG. 3. MEASURING INTERlFACIAL TENSION
capillary D a very slow flow of oil may be obtained at B by opening the stopcock C. The orifice is immersed in a beaker of water, and the number of drops formed by the given volume of oil in A is counted. The surface tension oil-water is inversely proportional to the number of drops.2
A series of mineral oils were tested with this instrument, and then a series of animal and vegetable oils and compounded oils.
The following table shows a few results selected from a very large number of trials:
TABLE I
|
Table of Interfacial Tension by Drop Numbers of Various Oils Against |
||||
|
Water. |
- |
|||
|
Mean temperature 70° |
F. |
|||
|
No. of drops |
Tension in |
|||
|
OIL. |
at constant |
arbitrary |
||
|
orifice and |
units. |
|||
|
head. |
||||
|
Parafflnura liquid um .. 95 |
.. 100^ |
|||
|
0-905 mineral |
101 |
94! |
Mineral |
|
|
Solar red mineral . . |
102 |
95 f |
oils. |
|
|
Hon- viscous neutral |
99 |
93 J |
||
|
Olive |
132 |
72\ |
||
|
68l |
Fatty |
|||
|
59 f |
oils. |
|||
|
73) |
A glance at the table shows the surprising fact that the interfacial tension against water of the vegetable and animal oils is much lower than in the case of a mineral oil.
What is more, we were struck by the fact that we had here a test which showed a distinct physical difference be- tween mineral and saponifiable oils independent of viscosity, density, etc., and this difference appeared to be in conformity with the lubricating properties of the oils.
It now remained to inquire what was the reason for the difference in tension. After considerable experimentation we proved that the lowering of the interfacial tension against water in the case of fatty oils was due to their slight content of free fatty acidity.
The following table shows some of the results: TABLE II
|
Free fatty |
Drop no. |
Interfacial |
|
|
OIL. |
acids, calc. as oleic. |
tension. |
|
|
0 005 mineral |
nil |
101 |
100 |
|
98% mineral |
! 1-9 |
125 |
80 |
|
2% com. fatty acids . |
( i x> |
||
|
97% mineral. . |
I 2-8 |
130 |
78 |
|
3% com. fatty acids . Olive |
1 2-2 |
125 |
80 |
|
Olive |
4-5 |
140 |
72 |
|
Rape Coconut |
2-5 4-1 |
132 148 |
76 68 |
|
Olive (neutral) |
01 |
110 |
92 |
|
Rape (neutral) |
0-15 |
108 |
93 |
By removing the free fatty acids from the saponifiable oils the tension rises, and by adding free fatty acids to the min- eral oil the tension can be lowered.
Now all commercial animal and vegetable oils contain small quantities of free fatty acids, and even if the utmost care has been taken in refining to remove the acidity, hydrolysis soon sets in and free acids are formed which, in even rela- tively minute quantity, suffice to lower the surface tension. Table III shows the percentage of free fatty acids in repre- sentative samples of animal, vegetable and compounded oils on the market. It is representative of the general glycerides and commercial compounded lubricating oils in daily use on all types of power plant, and we see that fatty acids are always present to a certain extent. From the foregoing it is demonstrable that:
1. Capillary effects (hitherto ignored in lubrication) play a fundamental part.
2. The presence of fatty acids in an oil lowers the surface tension of said oil against water.
3. A neutral glyceride possesses a similar tension to a neu- tral mineral oil.
4. The addition of a relatively minute amount of a fatty acid to a neutral mineral oil reduces the tension to that of a commercial animal or vegetable oil or compounded lubricat- ing oil.
2Donnan, Zeit., f. Physifl. Chem. Vol. 31, etc.
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SCIENTIFIC AMERICAN MONTHLY
July, 1920
Now it remains to inquire how far these results influence the theory and practice of lubrication of solid surfaces. It might toe argued that the interface between oil and water is a different thing from the interface between oil and metal, and that the conclusions drawn from the one case are not necessarily applicable to the other. As a matter of fact such similarity in effect is not unknown in other instances, and to obtain more conclusive evidence Professor Lewis has meas- ured the interfacial tension between oil and a liquid metal — mercury. (It should not be forgotten that solid-liquid inter- facial tension cannot be measured.) His results are as fol- lows : Pure neutral mineral oil, 100 ; same mineral oil plus 2 per cent of commercial fatty acid, 89. It is seen that again there is a lowering in the interfacial tension as a result of the addition of the organic acids, and, what is more striking, the relative lowering produced is very much the same as it is in the case of an oil-water interface.
Professor Lewis remarks : "One may conclude therefore with some confidence that the addition of the organic acids will lower the tension at any metal-oil interface."
Again, as already pointed out, the permanency of films is dependent upon a diminished interfacial tension between the oil and the metal in contact therewith. If such a film is broken the possibility of its uniting again to form an un- broken layer depends entirely upon the interfacial tension being low. Any substance which lowers the interfacial tension TABLE III
Acidity (as oleic). Animal oil, pale . . . . . . . . . . 4-2 to 25-55
„ brown . . . . 12-02 to 30-32
Castor, firsts 0-49 to 1-70
.. seconds . . 2-12 to 7-40
Coconut, Cochin 1-26 to 19-11
Colza, Belgian 1-97 to 3-22
,. Stettin 1-41 to 4-48
Lard, pressed - 0-28 to 0-71
Olive oil, Algerian 2-52 to 13-72
Gallipoli i 12 to 33-14
Palm oil 24-68 to 5605
bleached 14-1 to 27-49
Kane oil. Black Sea. refined 1-82 to 4-34
East India 1-26 to 4-24
Sperm oil, Arctic no. 1 0-56
„ no. 2 0-42 to 4-34
Southern 0-7 to 2-86
Tallow . . . . ' 1-55 to 43-71
Standard Brands of Compound Oils on the Market :
Acidity (as oleic).
Marine engine oil, D 1-3%
O 515%
T 4-5*y
Motor oil'.' X ".. '.'. '.'. '.'. '.'. '.'. 0-26%
Y 0-5%
Z 2.5%
Compound steam cylinder 0-4%
Medium gas and oil engine oil 0-25%
0-39%
Light gas and oil engine oil 1-6%
1-3%
Heavv gas engine oil 1-28%
2*5*/ Oil engine oil ". . '. . '. . 0-7%
causes the liquid to spread over a larger area of the solid. It follows therefore that if a substance be added to an oil which brings about a lowering of interfacial tension, such addition will act favorably as far as lubrication is concerned by preventing a rupture of the liquid film and preventing in turn the metals from coming into direct contact.
The capacity for spreading may be considered as partly physical and partly chemical, due presumably to residual valency. The effect is to render the transition layer between the liquid and solid less abrupt. This diminution in abrupt- ness can be brought about by chemical action direct or indi- rect across the transition layer or by the solubility of some third substance in both phases.
H. S. Allen has recently pointed out that on Langmuir's view oiliness depends on the chemical forces called into play between the active part of the oil molecule and the solid surfaces of the bearing.
Now it is obvious that there is a tendency for chemical activity between the metallic surfaces of bearing and journal and an oil containing free fatty acidity, while such tendencies are less pronounced in the case of a neutral mineral oil. Such a tendency would render the transition between oil and solid
surfaces less abrupt, would manifest itself by reduced inter- facial tension, and would result in better spreading and conse- quent increased efficiency in lubrication.
There is little doubt in our minds that the physical rationale of the property of "oiliness" is now explained, and we have confined ourselves so far to a statement of the physico- chemical experiments which we have made and to the de- velopment of the physical theory.
Conclusive as it appears to us we have proceeded to test and verify the conclusions by direct friction measurements, and finally by the only real touchstone, namely, the test of experience in a long series of practical trials on all types of machinery and prime movers of the very largest sizes.
We will proceed to consider some of the results in detail.
First we beg to tender our thanks to Mr. L. Archbutt for the frictional test made by him, which he has communicated to the Physical Society at its recent discussion on Lubrication.
Archbutt has made a series of determinations of the fric- tional coefficient on a Thurston machine under a load of 270 lb. per sq. in. at the very slow speed of 7 ft. per minute.
His results are as follows: Pure mineral oil, 0.0047; do. plus 1 per cent rape oil fatty acids, 0.0033. He finds that 1 per cent of free fatty acids lowers the coefficient as much as does 60 per cent of pure rape oil (acid-free).
These results have been confirmed by us on an independent machine, as we shall show later.
He has also shown, however, that pure neutral rape oil also possesses a lower coefficient than mineral, and concludes that "these results would suggest that the oiliness or lubricating efficiency of the unsaturated molecules of rape oil was really as great as that of the free fatty acid molecules, but that the acid molecules were much more active in their influence on the hydrocarbon molecules of the mineral oil."
These results, which show that 1 per cent of free fatty acids of rape oil added to a mineral oil are as effective in reducing the value of the frictional coefficient as is the addition to the mineral oil of 60 per cent of neutral rape, are striking confir- mation of the above described principles, and coming from a totally independent and unbiased experimenter afford great support to our contention that it is not the glyceride but free fatty acids in a compounded oil which improves its lubricating value.
Through the courtesy of one of the largest engineering firms in the country we have been enabled to make a series of meas- urements in a large friction testing machine, the results of which we here reproduce : The test journal of the machine — which is of the Thurston type — is 3.8 in. diameter, giving ap- proximately one foot peripheral per revolution. The length of the journal is 6% in., and in all our experiments the load was 200 lb. per sq. in. The machine is provided with a revolution counter and a drum upon which the reading of the arc is automatically traced. The driving motor was operated by a variable speed controller, and all care was taken to ensure steady and constant speeds. The journal and bearing were thoroughly cleaned before each test by washing with tolulol, and finally rotated against velvet pads to remove all super- ficial dust and moisture. The experimental temperature was kept between 60 and 64 deg. fahr.
The values of the frictional coefficients calculated from the curves obtained directly from the machine are given below.
By way of illustrating our point, four oils were chosen of identical viscosity and density but differing in composition thus:
These results afford great support to the views expressed above, and, coupled with our experience in practical lubrica- tion, about to be mentioned, confirm our explanation of the property of oiliness and open out a new and invaluable field in the manufacture of lubricating oil.
We should here mention that this principle of making lubri- cating oils by adding to mineral oils small quantities of fatty acids or substances which lower the interfacial tension has been accepted by the Patent Offices in all civilized countries.
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SCIENTIFIC AMERICAN MONTHLY
35
We should add a word here with regard to the possibilities of corrosion.
As will be observed from the table below, all compounded oils which have been and are in daily use for years contain notable amounts of free fatty acidity, yet one rarely hears of any active corrosion.
In our case we add only very minute amounts of fatty acids, and the quantity is strictly limited and controllable. But where fatty glycerides are employed the amount of acidity which can fortn is potentially very large because hydrolysis is constant, giving rise to the production of free acids.
During recent years a great deal of attention has been devoted to the study of the colloidal characters of the fatty acids, and it has been shown that while the lower members of the fatty acid group possess relatively little colloidal character, the higher members are highly colloidal in charac- ter. Donnan and Potts have shown that there is a grada- tion in these properties as one ascends the scale, lauric acid occupying a sort of intermediate position. Also the lower members of the series possess strong acid characteristics, while the higher members are very weakly acid. Now the fatty acids which occur in commercial oils are never pure chemical individuals, but are mixtures in varying proportions of a considerable number of fatty acids. Coconut oil, for example, is characterized by containing appreciable percent- ages of the lower members of the series, while rape oil rarely contains anything but the higher members.
It is only to be expected, therefore, that the behavior of these oils will differ in accordance with the fatty acid groups
Not a single failure has occurred in practice of an oil or an oil "essence" made on the "germ process" as a reliable lubricating oil when used for the purpose for which it was supplied. The