Page:Popular Science Monthly Volume 56.djvu/681

Rh on their luminous surfaces these shadows and to make them evident to the eye. An interesting use of flexible sensitive films instead of glass plates has been made in dentistry. The films are put in the mouth, and the Crooke's tube placed outside in such a position that the rays can pass through the jaw. In this way the accompanying photographs were taken (Fig. 4).

The use of photographic films in the application of the X rays in surgery will doubtless extend; we can easily imagine cases

 4.—1. Male patient, aged ten years. Temporary incisors in position with the permanent incisors nearly ready to erupt. The roots of the temporary teeth nearly absorbed. Right temporary central cut incisor destroyed by a blow five years previous, showing gutta-percha filling put in at the time which, with the dead root, has been absorbed (same as the live root of the other central). It is taught in the text-books that teeth with dead nerves are not absorbed. 2. Temporary molars in position with no signs of the permanent bicuspid which should take its place. 3. Patient, aged ten years. Shows the open ends of the incisor roots. 4. Shows one bicuspid and two molar teeth. The roots of the teeth pass through the floor of and into the cavity of the antrum. The spongy character of the bone is shown. 5 and 6. Superior jaw, right and left sides, showing temporary cuspid teeth in place, with the permanent cuspids imbedded in the jaw entirely covered.

where the necessity of the use of the knife may be avoided by the information which a carefully placed film might afford. In general, X-ray photographs convey more information to the skilled eye of the specialist than to the untrained inspector of them. They should be studied from the negatives themselves, for the delicate details can not be reproduced in a print. It is remarkable that shadow pictures can show go much definition. Here is a