September io, 1896J 



NA TURE 



45: 



forced tu use greater currents than might have been expected. But 

 throughout the experhiients, either upon fluorescent screens or 

 in photnijraphy (I do not meantime enter upon the question of 

 whether the maximum luminescence on the screen is the proper 

 conditii>n for obtaining the best result on the sensitive plate), 

 the conditions were kept as nearly as possible uniform. In 

 a previous paper in Nature, I pointed out the advantage 

 of a g.iod interrupter, emphasising in attempts at instan- 

 taneous photography the value of the mercury form ; 

 but whether we use the latter or render the screw of the Apps' 

 coil more tense so as to get larger sparks, any one watching the 

 effect upon the ampere-meter and the fluorescent screen at the 

 same time, will soon appreciate how important it is to control 

 the current by means of the rheostat throughout the experiment. 

 I have made experiments upon different kinds of glass for tubes ; 

 different sized kathodes ; thicknesses of anodes ; various materials 

 for the latter ; tubes have been sent tome by Mr. Friedrich, with 

 a request that they might be compared with English forms ; 

 the Berlin Electrical Company have also 

 placed their tubes at my disposal, but 

 after many trials I know nothing so im- 

 portant as the constant attention to the 

 vacuum throughout the exposure. Some 

 of the best photographic results in the 

 deeper structures of the body were ob- 

 tained by the small and earliest form of 

 Kewton's tube. Another method of control 

 is to place the two poles attached to the 

 secondary coil at a certain distance from 

 each other. This, of course, is used in 

 testing the length of the spark before be- 

 ginning the experiment. If these be too 

 near during the exposure the sparks fly 

 across, and the current being short-circuited 

 the tube is cut out, but when the space 

 is increased the tube becomes luminescent. 

 This distance should be noted, and may be 

 used to control the amount of electricity 

 passing through the tube, as alteration in 

 the vacuum causes the sparks again to fly 

 across. By means of the spirit lamp or 

 Bunsen burner a little heat applied to the 

 bulb at once corrects the vacuum, and a 

 certain uniformity of condition within the 

 tube results. 



It may here be pointed out that in using 

 fluorescent screens for the deeper structures 

 of the body, barium-platino-cyanide in 

 some instances gives a better result or a 

 darker shadow than the potassium salt. I 

 am quite aware of the fact that the potas- 

 sium is more luminous, and it may be that 

 it is a matter of construction of the screen 

 or the particular specimen employed, be- 

 cause samples of these salts vary in their 

 effects. After using a large number of 

 different materials I, like others, have 

 fallen back entirely upon the potassium 

 •or Ijarium salts, but employ both, and the 

 barium has the great advantage of being a 

 good practical agent well suited for hospital Fig. 3.- 



purposes, and durable. I have still in my 

 possession a screen made of this salt early 



in March of this year, and, although small in size, it gives as good 

 results as any of my newer screens. I find a darkened room for 

 medical inirposes much better than any form of cryptoseope. 

 tinder favuurable conditions many parts of the face and head can 

 foe distinctly seen on the screen. In some instances I have seen 

 foreign bodies, such as shot in the scalp ; in another I was able 

 to differentiate, in a case of paralysis of the extremities, between 

 fracture of the skull with pressure on the soft tissues from the 

 «ffusion of blood and obstruction due to a star-shaped fracture, 

 as opposed to the diagnosis of a bullet which was thought to be 

 situated at a particular spot. The tissues of the neck may easily 

 be searched for foreign bodies which obstruct the rays. Photo- 

 graphs of all these can of course be obtained, and I need hardly 

 point out that, in the present state of our knowledge, the photo- 

 graphic plate reveals in some instances what the screen fails to 

 show. There is one curious exception to this, where the move- 

 jttients of the organ are rapid, such as in the heart, because this 



necessarily interferes somewhat with success owing to the move- 

 ment during the exposure of the plate. Passing to the chest, the 

 outline of the pleural spaces may be seen, and in one case con- 

 densation of the apex of the lung was thrown as a shadow upon 

 the screen. The heart itself as a body in motion, the ascent and 

 descent of the diaphragm, the liver covered with the diaphragm, 

 can also be made out. The majority of those conditions have 

 been photographed as well as observed, and I have a seties of 

 pictures showing enlargement of the heart, enlargement of the 

 liver, and in one case renal calculus. It need hardly be said 

 in addition that every part of the trunk and extremities, as far 

 as the osseous parts are concerned, have been photographed. 

 I do not use fluorescent screens in photography, one amongst 

 other reasons being that the plates used were much larger than 

 any screen in my possession. 



While these statements seem to indicate considerable progress 

 in the art, I desire expressly to interpret them in the light a 

 surgeon uf physician would view them, lest any misconception 



rimitiei (aJult), faint shadows of 



should result. When one reads of instantaneous photography, 

 direct inspection or photography of so many of these tissues, it may 

 be argued that we have now brought the subject to a thoroughly 

 practical issue ; but it is not so. For this reason I have placed 

 these statements before your readers, in the hope that those 

 engaged in the physical research may know how much we are yet 

 in need of their aid. Take the statement of rapid or instan- 

 taneous photography ; a careful perusal of the valuable summary 

 in the p-iges of Nature for April 30, shows that this statement is 

 applied to the extremities for the most part. It need hardly be 

 pointed out that what the surgeon desires is instantaneous photo- 

 graphy of every part of the body, particularly where there is 

 movement. Further, the reader may imagine that in seeing 

 the movements of the heart, one can examine it much as the 

 physiologist does the beating of the same organ in the frog 

 during dissection ; but it is not so. Before the movements of 

 the diaphragm and heart, the limits of the pleural cavities, and 



NO. 1402, VOL. 54] 



