The average audience before the micro-cinematographic film is very much in the attitude of the schoolboy in the natural history lesson. Scarcely any other subject holds such possibilities of interest for him; yet the instruction must be given in some vivifying form, or it fails to touch his latent sympathy, and becomes a tiresome repetition of formulæ and inexplicable processes. Similarly an audience will sit absorbed before a film displaying infinitesimal organic life; but only on condition that its human instincts are in some way appealed to. Science lessons must be humanised, when they rival the most dramatic films in interest.

Unfortunately the supply of this kind of film is extremely limited. Producers are not convinced of the heartiness of the demand; and the labour, expense, and anxiety attending the preparation of such subjects prevent their development upon any but a small scale.

An account has been given of Dr. Comandon’s wonderful achievements in bacteriological micro-cinematography, through the firm of Pathé Frères. In popular science the world’s market is practically supplied by an English company, Kineto, Limited.

This fact is due mainly to Mr. F. Percy Smith, who possesses the happy faculty of investing his subjects with a quaint fascination which compels appreciation. It is doubtful whether any film has stirred popular interest so intensely as that which he prepared for the purpose of illustrating the physical energy possessed by the common house-fly.

When this film appeared the newspapers far and wide associated the cinematographer with strange powers, and the capacity to train the bluebottle in much the same way as the lion tamer subdues the King of the Forest. Nothing was farther from the truth. The scientist merely devised unusual and novel devices to illustrate the points which he had in mind, and the fly was left more or less to follow its own devices. For instance, it was seen to walk again and again up the rim of a small wheel in a vain effort to reach the highest point. “Trickery!” was the verdict when the film was seen first, and it was hard to make people believe that the picture was genuine. As a matter of fact, the fly performed the operation quite naturally, though in order to induce it to do so the experimenter had to resort to an ingenious device.

A dark box was prepared with a very small door of thin glass at one end. This piece of glass was fitted with a narrow slit in which a small toothed wheel, similar to a watch escapement wheel, was fitted in such a way as to be free to revolve. The imprisoned fly, seeing the daylight entering through the glazed end of the box, attempted to escape in that direction, but found its passage obstructed by the glass. When it struck the latter, it received a smart tap on the head from a tooth in the wheel, which was caused to move through the fly’s frantic efforts. Time after time the fly threw itself against the glass door, and on every occasion it received a rap on the head. At last frenzy gave way to tractability, and it came to the conclusion that the best means of escape was by walking up the wheel. Of course, as it advanced the wheel slipped round in the opposite direction. While the insect was walking like a criminal on a treadmill, the pictures were taken.

The results with the fly under restraint, however, were not entirely satisfactory, so the experimenter set up the wheel in the open, and withdrew a fly from its prison after it had become tractable. Time after time the blue-bottle would fly away directly it was placed on the wheel. The camera, however, was kept in readiness for exposure the moment a fly did attempt to walk along the rim, and at length it was successfully caught in the act. Again, the fly was laid upon its back beneath the wheel, and was seen to revolve the disc with its legs. The simple explanation of this seemingly clever juggling trick was that the fly thought it was walking in the same way that it walks up a wall or along the ceiling.

One fly in the same film was seen seated in a diminutive chair nursing a smaller fly, or balancing and juggling with articles such as tiny dumb-bells, but of large size in comparison with its own bulk. In this instance the fly was secured by a thin strand of silk passed around its body; but here again, in performing the apparent juggling feats, it was merely following its instinct. Being prevented from flying, it naturally endeavoured to make progress by walking.

The fly was to be seen endeavouring to balance a piece of cork, and intense amusement was caused when it was seen to wipe its feet, in the same way that a man rubs his hands together, preparatory to making some kind of effort. In reality, the fly found that the suckers on its feet, by means of which it secures a grip upon a surface when walking upside down, were somewhat dusty. The apparent preparation for a herculean attempt was nothing more than the fly cleaning its organs to achieve its purpose.

This film occupied several weeks in preparation. Extreme patience had to be exercised, and when a desired phase of movement had been secured, often it was found defective from the technical point of view, so that the wearying round had to be repeated. Recently Mr. Smith has continued his investigations, and has produced another fascinating film, demonstrating still more clearly the tremendous physical energy possessed by the bluebottle, and the wonderful powers of its proboscis, the movements of which, to assist the legs, are shown very distinctly.

Another of Mr. Smith’s achievements is the film showing the hatching of a chicken’s egg. The period of incubation is extended over 21 days—about 500 hours—and the egg naturally has to be preserved at an even temperature the whole time, so some special means had to be devised to make the film without imperilling the life of the embryo. The opaqueness of the shell constituted a formidable stumbling-block. Moreover, in the initial stages the embryo is so small, and its movement so slight, that little difference is observable for the first 50 hours or more. Direct photography was seen to be out of the question.

An incubator was acquired, and the eggs were placed in it. At regular and frequent intervals during the incubation, some were withdrawn, and opened to ascertain the size and position of the embryo.

From these data diagrams of the early stages were prepared. They were drawn carefully to scale and accurate in every detail. This task had to be continued during the first 54 hours—the period when the movements of the embryo were unknown—and involved the preparation of no fewer than 1,000 diagrams, prepared in such a way that they resembled photographs. From the number of these records and the period occupied in incubation, it will be seen that they were prepared at intervals of about three minutes during both day and night. This consecutive series were then cinematographed upon the film, and thus a natural development lasting 2½ days was reduced to a period of about one minute upon the screen.

The early part of the film is not so interesting to the public as that showing the chick coming out of the shell. Here again an initial difficulty was encountered. The hatching, of course, could not be cinematographed inside the incubator; and to remove the egg from the temperature of 103° in which it had been kept was to arrest the process at once.

Fortunately the experiment was being made in summer, and the thermometer read 103° in the sun. The camera was set up, and at the moment the chick gave signs of breaking through its shell, the egg was removed from the incubator and placed upon a table in the full glare and heat of the sun. In a few seconds the chick made further efforts to break down the walls of its prison, and very soon made the first breach in the shell. As the heat of the sun was exactly that of the incubator, hatching was continued under precisely natural conditions. It was not long before the hole in the shell was widened sufficiently to enable the chick to wriggle its way into the world. From the cinematographic point of view, the hatch was as perfect as could be desired, especially as the chick was strong and active after hatching.

Mr. Smith once ventured into the Sussex woods, to obtain some animated photographs of the British adder in its natural haunts. He succeeded in tracking down an excellent specimen, of which some first-rate pictures were taken. Then he proceeded to record on the film the methods by which this reptile may be caught and handled in safety. While holding a large specimen in his hand he provoked it to fury, and caused it to strike out savagely, so as to secure on the film some life-like pictures of an adder striking, as well as details of its mouth and fangs. As a contrast, he then decided to show how an adder should not be handled. He took the precaution to chloroform the reptile before mis-handling it, but the snake recovered too soon from the anæsthetic, and striking out with its fangs, caught the investigator a smart blow on the hand, leaving two minute punctures. The bite of the adder is seldom fatal, but, contrary to popular belief, it is far from harmless, producing delirium and precipitating collapse, recovery from which occupies several hours, or in some cases even weeks, as Mr. Smith found to his cost.

An unusually successful popular science film is the one showing the development of a flower from seed to blossom. It has been encored more than once on being presented.

The average plant demands several weeks from seed to blossom. Mr. Smith made an ingenious apparatus for securing a continuous representation of growth. The seed was shown first in the initial stages until the embryo burst from the protective or outer shell or husk; and then continuously from the moment the first sign of the shoot appeared above the level of the soil.

The camera was set up and an automatic apparatus attached thereto, which enabled an exposure to be made at predetermined intervals both during the day and night. The apparatus was driven by a curious motor which obtained its power from dripping water; and the arrangement was such that, after the exposure was made, the film was moved forward to bring the next area of sensitised surface before the lens. The receptacle containing the seed was placed at the correct distance to ensure a large picture, and for the purposes of illumination at night a special device was connected to the driving mechanism of the camera, whereby the subject was brilliantly illuminated at the instant of exposure. The exposures were made at average intervals of thirty minutes, giving forty-eight exposures at different stages of the growth in the course of the twenty-four hours. When projected on the screen at the normal rate of sixteen pictures per second, it looks as though the growth of the plant had been forced to about 30,000 times its usual speed, with the camera continuously in operation the whole time.

The great secret of Mr. Smith’s success is the simplicity of the apparatus he employs for his work. Each subject demands special arrangements. His contrivances for the most part are extemporised from crude materials; even the microscope, which he sometimes uses, being of the simplest and cheapest pattern. He has found that elaborate apparatus often complicates his work without producing such good results as are procurable by the most primitive devices.

Work in this field is attended with some curious results. The eyes of some of the lower animals are extremely fine lenses, and unless care is bestowed some sorry tricks are played at the expense of the scientist. Mr. Smith related to me that on one occasion he secured an excellent series of pictures of the frog at close quarters; and congratulated himself upon his success. His dismay was great when he projected the pictures for the first time. Although the frog itself was beyond reproach, interest in it paled before the unexpected sight of the operator turning the handle of the cinematograph, reflected with great distinctness in the frog’s eye.

There is one great difficulty attending the photography of the smaller organisms of Nature which is very difficult to surmount; that is, unnatural results arising either from the disturbance of the object under examination, or its photography in a false environment. This complexity is emphasised very strongly in connection with cinematography. If it is desired, for instance, to record garden pests engaged in their destructive work, it is trying indeed to convey a correct pictorial description of their methods. Troubles concerning illumination are particularly baffling of solution. Mr. Smith has devised a special apparatus, which is very similar in its general characteristics to a heliograph, mounted upon a tripod stand so that it can be revolved in any direction. With this parabolic reflector the sunlight can be brought into position and concentrated upon the subject under cinematographic observation without disturbing it. The photographs by this means of insects at work, no matter how unreal they may appear at first sight, are absolutely true to Nature, and are taken under incontestably natural conditions. In fact, the ray of illumination thrown upon the object by this means is so brilliant as to enable subjects to be photographed in their natural colours; which fact may in the future afford scientists a wonderful opportunity of studying protective colouring in insects.

It is probably beyond dispute that the popular scientific film, treated in such a manner as is indicated in this chapter, is certain to command the approval of the public in the end. At the present moment the popular scientific cinematograph picture is in its infancy. It will be only through the perseverance of the scientist who has the happy faculty of amusing as well as entertaining a general audience that this class of film ever will have a vogue. The tendency towards this state of affairs, happily, is improving every day, for the cinematograph is appealing more and more to the cultured classes, who, after all, constitute its most substantial support.