The clinical application of the Röntgen rays.

Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The clinical application of the Röntgen rays. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    of light and shade. For much work the whole tube may be used, and a fairly definite outline secured by setting the vacuum-tube at a greater distance from the photographic plate. When the radiant source was that portion of the tube which was exposed by the circular hole in the lead diaphragm, the vacuum-tube could be set about 6 or 8 inches from the plate, and a good picture taken of thin objects, like the hand, by an exposure of one hour. When the whole tube served as a source, an ex- posure of an hour for the thinner and an hour and a half for the thicker objects was sufficient, the tube standing 12 inches or more from the plate. It should be noticed that the outline will be better and success more cer- tain if those parts which are specially desired are brought as close to the plate as possible. The proper relative positions of object, plate, and tube may be readily seen by remembering that these pictures are shadow- pictures, and that if for the vacuum-tube we were to substitute an equally large globe of ground glass, illuminated from within, the object would cast a shadow on the plate very like that which it makes in the Rontgen rays. The arrangement which will cast the best defined shadows of the desired object will yield the best results. The photographic plates are developed in the ordinary way. As the pictures are only shadows, and no artistic effect is required, the devel- opment can be pushed further than would be suitable with an ordinary plate, with the result sometimes of bringing out detail that does not appear at first. The skiascope, to which reference has already been made, is an instru- ment designed to take advantage of the fact that the Rontgen rays cause fluorescence in certain substances, to make direct visual observa- tions of these rays and the shadows cast by them. The fluorescent substance which I have used is the double cyanide of platinum and barium, which is so excellent for the observation of the ultra-violet rays of light, and whose usefulness in connection with the Rontgen rays was announced by their discoverer. Much of the salt which I have obtained from the chemists either exhibits no fluorescence at all with the Rontgen rays, or only a trace of it, and I cannot at present state the conditions of preparation which will insure good fluorescence.1 The successful results which I obtained were secured with a piece of platino- bari-cyanide paper imported from Germany recently for the Princeton cabinet. A circular disk cut from this paper was fastened, with the fluorescent side inward, by non-actinic black photographer's paper in one end of a brass tube blackened on the inside. By fitting the other end of the tube around the eye, both the eye and the fluorescent sub- 1 Dr. G. D. Rosengarten has investigated for us the chemical and physical properties of the platino-bari-cyan ide.