176 EOYAL SOCIETY OF CANADA 



There is little evidence at present of any kind of selective absorption, 

 but if an}' phenomenon of this nature exists, as in the case of ordinary 

 light, it should be possible to find some fluorescent substance which was 

 particularl}^ sensitive to the rays which are specially absorbed by bone. 

 We did not ourselves make any experiments worth mentioning in this 

 direction, because it happened that the photographic plates which we 

 first used. Stanley, sensitometer 50, appear to give results which from 

 all accounts were at least equal to those which were obtained elsewhere 

 Avith the aid of fluorescent screens. The following list, comprising the 

 more diflUcult cases which we have attempted, will serve to illustrate the 

 possible applications of the method. 



Bullet in brain of child, aged 12. The bullet and the hole by 

 which it entered are clearly shown in a i)hotograph with an exposure of 

 nine minutes. The bullet was faintly visible on another plate with an 

 exposure of three minutes. It was found to have settled down nearly in 

 the centre of the brain. 



Broken hip joint. An exposure of tifteen minutes was allowed for 

 this case, as the subject was a man of solid build. The head of the 

 thigh bone was found to have been broken ott and twisted round. The 

 foramina and other details of the pelvis are clearly shown.* The nega- 

 tive is so dense that it lakes more than half an hour to print in bright 

 sunshine. 



Drainage tube in lung. This was a case of a small drainage tube 

 of ebonite, No. 9 catheter, which was lost in the lung eleven years ago. 

 Owing to its thinness and to the comparative transj^arency of ebonite, 

 the tube was a somewhat faint object, but was quite unmistakably 

 visible in the negative. 



Fracture of skull. The subject had been gored b}' a bull two 3'^ears 

 ]»reviousl3', '^'"^ '"^'^ ^"^^ <^'i6 eye and part of the bone of the orbit. lie 

 had lately become subject to flts. The negative showed a vague white 

 shadow in the neighbourhood of the gap in the skull, which may have 

 been due to a piece of displaci'd bone, or to some bony growth. The 

 indications are too indefinite, however to be of much use in diagnosis. 



Pus cavity in lung. In this case the diagnosis from the ordinary 

 methods was very uncertain. A cavity, however, was very clearl}- indi- 

 cated as a dark shadow in the negative. If the cavity had been full of 

 pus at the time, it would have been indicated as a lighter patch, the 

 transi)arency of liquid heing less than that of lung tissue when distended 

 with air. 



Stone in kidney. Some of the typical syin})toms were absent in 

 this case. The X-ray negative showed a faint wliite patch in the region 

 of the kidney. 



In addition to the above, which include the more ditlicult medical 

 cases, a very large number of simpler cases of fractures, etc., of the 



