red

of an aeroplane. The imagination can find nothing in the daily life of human beings more thrilling and wonderful than some of the scenes presented to the silent and awe-struck spectators of the performance at the house of Masson Brothers. They saw on the screen, in that room all darkened and hung with black draperies to heighten the effect, first an animated scene enacted in the delicate network of capillaries, or tiny blood-vessels, in the foot of a frog. Innumerable globules struggled with one another like a frightened crowd of people trying each to be the first to escape from something through a narrow passage. The white globules, those carnivorous animals of the little world that circulates in our bloodvessels, attached themselves to the red globules, enveloped them and devoured them. Everything was in motion; the tiny creatures lived, struggled, fought; it was the old story of all life on this planet-the strong driving, oppressing, devouring the weak; eternal and pitiless battle for existence. And it left a curious feeling in the hearts of the spectators.

There followed a peep into the bloodvessel of a bird, where little dart-like

creatures, twisted as

so many cork

screws, dashed about in their headlong career. These were the spirochetes gallinarum-parasites which kill the fowl in certain regions of South America, and which are near relative to well-known microbes that afflict human beings with their terrible ravages. Among the healthy red globules dashed these murderous savages of the blood, with movements like serpents up and down the screen of the cinematograph. They attached themselves to one another, flung off, attached themselves again, whirled, darted, danced like veritable cannibals before a feast. Then suddenly one of them would dash out, leap on a red globule, pierce it with incredible swiftness. Sometimes the spirochete would remain imprisoned in the red globule, despite its struggles to escape; other times it emerged after a frantic agitation. Then here and there appeared a white globule, moving slowly through the mass, and when it encountered

red globule that lacked the speed of most of its fellows the white attacked and devoured the red and moved ponderously on its way again.

Next came a drop of the blood of a mouse which had been infected with the microbe of that sleeping sickness which

ravages the animal life and even the human life of interior Africa. These were eel-like creatures, provided along their entire length with undulating fins. These too attacked and consumed the red globules in the blood. And here again were the large white globules, which indicated that the mouse had eaten some fatty substance which gave birth to them in the process of digestion. Other scenes were presented, showing various. kinds of microbes, some provided with claws, with tusks, with tentacles, with strange members that enable them to move and cling and prey upon the healthy elements in the blood, many of them so infinitesimal that a cubic millimeter held two millions of them. And to make them visible in these wonderful moving pictures required their enlargement by 10,000 to 20,000 di

ameters.

his work of examining them.

The solution of this difficulty was the invention of the ultramicroscope. In this wonderful instrument two things are to be noted. In the first place the light is thrown on the object, not from beneath it, but laterally, from a lamp placed at one side of the apparatus. In the second place a prism of glass, or parabolic condenser placed beneath the object to be examined, receives the light, and throws it on the object refracted in such a way that none of the rays enter the tube of the microscope. The object of investigation appears then under the lens like objects that are luminous in themselves, like the planets, for instance, which receive laterally the rays of the sun and therefore stand out, as it were, on the background of the sky. The microbes under the ultra-microscope, instead of being barely perceived on a luminous background, appear as bright spots on a dark background, and the work of the microscopist is advanced by a tremendous stride. Many bacilli that were invisible before are now brought within reach of the investigator.

This brings the story back to its beginning the microscope and its successor, the ultra-microscope. In the ordinary microscope the objects examined are seen by transparence-that is to say, a light beneath the objects passes through or around them and leaves them visible and magnified as dark spots on a luminous background. But by this method the light penetrated into the tube of the microscope, interfering with the vision; and, besides, if the microbes sought for were transparent, as many of them are, they were not distinguishable from the field in which they lay. Resort was had to coloring them to make them visible, but this method had the very depressing disadvantage of killing the microbes with the aniline coloring matter before the microscopist could begin

Dr. Comandon had long sought to ob tain a nearer and more precise vision of the world of bacilli. He is a true enthusiast, who says, "All those who have labored with the ultra-microscope know under what beautiful aspect appear certain preparations, and they have, withcut doubt, regretted not being able to preserve these images almost fairy-like and often of the highest scientific interest." He worked a long time trying to photograph these images under the lens of the microscope, but he invariably found that, even with the utmost rapidity

possible in the use of the camera the outlines of the microbes were blurred in the photograph and the life was no longer there. He pays a tribute to his He pays a tribute to his master and friend, Dr. Victor Henri, for having suggested to him the use of the cinematograph to catch this delicate and fugitive life and to bring it into the realm. of careful and leisurely study. Pathé Brothers, the great cinematograph makers of Paris, put their laboratory and factory at his disposition, and after two years of experimenting he was able to throw on a screen the moving pictures presenting the microbe world revealed in the full tide of its activity.

The apparatus as it is now perfected consists first of an electric arc lamp of 30 amperes, placed at one end of a solid table, at the other end of which is the cinematographic camera. and its machinery. Next to the lamp is a series of lenses for concentrating and modifying at will the rays of the electric light, and a diaphragm by which is cut off all the excess of the light beyond the rays centered upon the microscopic appliance. Then comes a disk of which the use will be explained later, and finally the microscope placed horizontally, with its eye piece at the lens of the cinematograph. The concentrated ray from the lamp is caught by the mirror of the microscope, thrown on the object to be photographed, and then, by means of the parabolic glass is diverted at an angle that prevents its entrance into the tube of the instrument. The machinery of the cinemato

graph is set in motion at the rate of 16 exposures per second, and the movements of the living microbes are preserved on the band of films. By the time they appear on the screen they are magnified as much, in some instances, as 30,000 diameters.

One of the greatest difficulties encountered by Dr. Comandon in his experiments was the intense heat developed by the electric lamp. A few instants of exposure to such rays of light is sufficient to kill the microbes which inhabit the preparation under the microscope. To remedy this, many appliances were tried without success before Dr. Comandon thought of a disk made to rotate very ingeniously in the path of the rays. This

disk is composed of sections open and closed alternately, and being synchronized with the cinematograph, it makes an alternating current of light, so to speak. The microbes are subjected thus to intermittent exposure, being under the heat only one-thirty-second part of a second each time, corresponding with the succession of films. To moderate still further the heat of the rays they are made to pass through a little reservoir of cold water between two of the lenses near the lamp. When the images have been taken on the band of the cinematograph the process continues precisely as in the case of preparing a street scene for the edification of an assemblage in a cinematograph theater.

"I do not insist," said Dr. Comandon, "on the manner in which the matter shall be prepared for

photographing with the microcinematograph. This subject has already been well treated by Dr. Gastou. It suffices to know that in general the drop of blood or infected matter is placed on one glass plate and another is pressed down firmly upon it till the preparation is spread out very thin between the two layers of glass. The uses to which we have put this microcinematographic process already are considerable. We were never before able to count the living inhabitants of matter because of their mobility: for example, the mobile particles of the blood which Müller has named hemokonies. Investigation with the ultra-microscope has shown that these animated particles have as origin the alimentary fats. An animal having absorbed a repast rich in fats, its blood swarms, two hours thereafter, with these hemokonies, which gradually disappear. By taking rapidly a great number of successive photographs, it is possible to count these lively particles, and to trace their growth and disappearance in the process of digestion. In the same way we watch the process of coagulation of the blood and the movements of every sort of microbe and, in short, every tiny process, healthy or malevolent, that takes place in the blood, in living tissues, in diseased flesh and in cultures specially prepared. I believe the microcinematograph will greatly enlarge the spheres of investigation of the biologist, the chemist and the bacteriologist."

"The consequences of this discovery," said Professor Dastre, of the Sorbonne, "are incalculable. All the movements microbian, all the movements brownien, so ill known today, will be studied now with a precision indescribable. In bacteriology we shall have, instead of fleeting glimpses into the world of bacilli, records fixed by which we shall study at our leisure. In short, many scientific questions that have baffled us are likely to be resolved, thanks to this new method.

Nature conceals much from us in the realm of the infinitely little, and I am prepared to hear of astounding discoveries and perhaps of successful battles with hitherto unconquered epidemics."

But this is not all, for Professor Pizon of the Lyceum Janson-de-Sailly, and his associates M. Vies and Mlle. Chevroton, have applied the cinematograph in another marvelous way. If there are natural phenomena which are produced with too great rapidity for us to seize their movements, there are others too slow for us to grasp their details. A plant is larger today than it was yesterday, but who has seen it grow? The bud of today is the rose of tomorrow, but though the wonder takes place under our eyes it is a mystery still. Cell growth of all kinds takes place at a pace too moderate to be synthesized. The experiments of Professor Pizon have been given little publicity up to the present time, but it is known that he and his associates are working on the principle that if the cinematograph can analyze very rapid movements by reduction of their speed in reproduction it can also synthesize very slow ones by increasing their speed in the picture. It was announced at the recent meeting of the Academy that Professor Pizon had succeeded in thus reproducing at appreciable speed all the curious transformations of that favorite subject of the biologist, the sea urchin. It is thus clear that the cinematograph will be employed in embryology, that branch of science which deals with the origin and development of organisms, and even in the study. of parthenogenesis, that branch of biology which deals with the still impenetrable mysteries of reproduction from the female without the intervention of the male. All these possibilities explain in some small way the enthusiasm which Dr. Comandon's and Professor Pizon's discoveries have aroused among the scientific men of France and of other countries of Europe.

I

IN France, where they are constantly experimenting with all known and every new sort of paving, an asphaltrubber combination is now being tested, in such cities as Paris, Lyons, and Marseilles. Europeans have been influenced, since the days of the Romans, by the magnificent roadways left by those sturdy civilizers. Modern wear and tear on roads, by motor, carriage and heavy wagon is far greater than in the days when the legions of Augustus or Vespasian, the chariots of the conquerors of distant peoples, or the hoofs of couriers' horses, passed over the Imperial highways that bound together Gaul and Persia. Present-day exigencies demand even more perfect roads than were required eighteen or twenty centuries ago.

Asphalt is perhaps one of the very best road-building materials in use today. The facility with which this substance can be molded, the rapidity with which it hardens, the comparative ease of repair, testify to its merits. But asphalt has disadvantages, and decided ones at that. It is costly, special plants for heating the powder and skilled workmen to lay and roll the heavy substance being required. Hence, small towns cannot well afford to make use of asphalt, and even many large cities hesitate to make use of this valuable substance despite its obvious merits.

Now in combination with rubberrubber-asphalt,-asphalt loses many of these disadvantages. According to M. Mazerolle, the French engineer, who presided at the International Road Con