Practical Cinematography and Its Applications

by Frederick Arthur Ambrose Talbot

In order to obtain sharp, clear, and distinct pictures upon the film, the subject under study had to be fixed in an immovable position. In the case of a trout a small celluloid envelope was made, fitted at each end with a small glass tube through which water necessary to the fish's existence was passed in a continuous stream. This vessel was only just large enough to contain the fish, so that movement was quite impossible. The top of the vessel was closed with a sheet of paraffin paper, which was placed in front of the aperture of the film gate. It was a very novel and successful means of radio-cinematographing a fish under natural conditions. The fish themselves appeared to suffer no ill-effects from the method adopted to keep them alive, a trout in one instance being kept in this confined position for two consecutive days. So long as an adequate supply of fresh water was passed through the celluloid vessel in which it was encased it experienced no trouble in respiration.

In the case of the toad and frog the subject was kept in a prone position by attaching thin ribbons to the legs and extending the latter to their utmost so that the digestive organs might be radiographed clearly, distinctly, and without difficulty. The lizard, which is very difficult to photograph, was secured in a similar manner. The birds likewise were attached by their legs, and had their wings extended so that the body came directly in the path of the rays. When young birds were under investigation it was necessary to maintain a circulation of warm water around their bodies so that the temperature might remain constant; otherwise the digestive functions might have been disturbed, thereby invalidating the value of the pictures. In one investigation a fowl was placed in a plaster cast so as to hold it perfectly still and steady.

The photographic speed was varied according to the character of the investigation and the subject. Thus, in recording the digestion in the stomach and intestine of the trout, an exposure was made every twenty seconds. In the case of the toad the speed was one in every ten seconds, while the chicken required one in every five.

One of the most novel experiments which Monsieur Carvallo carried out in this particular field was to ascertain the extent to which digestion will continue in the intestine after it is removed from the animal. The digestive tube of the frog was selected for this novel investigation and the photographs taken at the rate of one per second illustrate the fact that the digestive organ will continue its functions long after its removal from the body.

Since the year 1900 when Monsieur Carvallo carried out his scientific researches with the Röntgen rays, radiographic science has made great strides. Researches of this character no longer require elaborate and expensive apparatus. This has been shown by Dr. J. Comandon, the well-known French scientist, who, at the laboratories of Messrs. Pathé Frères, has prepared some magnificent X-ray films in such a manner as to make them interesting to the average patron of the picture palace. Dr. Comandon possesses the unique ability of so treating his subject as to make it appeal to the unscientific mind.

Fig. 10.—Dr. Comandon's radio-cinematographic apparatus.

In his system Dr. Comandon does not radio-cinematograph directly in the manner of Monsieur Carvallo, but has recourse to the fluorescent screen, thereby obtaining his results much more simply and easily. By this means, also, he is able to use the standard cinematograph camera and film without any modifications, the images upon the sensitized celluloid ribbon being of the normal size. The general arrangement of the apparatus used by this investigator is shown in the diagram ([Fig. 10]). A room is divided by a partition A. On one side is placed a camera F of the conventional type. On the other is the necessary electrical apparatus. An aperture B is provided in the partition, and this space is filled with a fluorescent screen. On one side of the partition A centrally in regard to the fluorescent screen, and a little distance therefrom, is placed the Crookes tube C, the subject under investigation being placed between the tube and the screen. Consequently, the radiograph is projected upon the fluorescent screen and this image is then photographed by the camera. At the normal photographing speed the exposure is about 1/32 second.

The fluorescent screen employed by Dr. Comandon is of the type known as "reinforced." It is covered with tungstate of calcium, instead of barium platino-cyanide. With this screen the Röntgen rays are intensified, or rather are transformed, the luminous radiation being rendered more actinic and therefore able to act more quickly upon the emulsion of bromide of silver with which the film is coated. By using this fluorescent screen the exposure is reduced to about one-tenth of what would be required were the subject radiographed direct.