84 



KNOWLEDGE. 



March, 1911. 



containing' a 

 that IS ciuite 



tumours, and obstructions in the digestive system. 

 The latter is a comparatively recent development, 

 and is one that is of great interest. The method 

 consists of giving jelly or other food 

 large amount of a bismuth conipouiK 

 harmless. The bismutli being 

 opaque to the X-ra\s the pro- 

 gress of the food can be 

 watched in its progress along 

 the digestive canal, and at 

 times the information gained 

 is verv valuable. There is a 

 great danger, howex'er. in mis- 

 interpreting the aiijiearances. 

 because similar shadows may 

 be made h\" \er\' different con- 

 ditions: in no instance is the 

 opinion of an expert more 

 necessary than in this. 



Bv means ot \cry [loxwrful 

 apparatus more or less instan- M — i 

 taneous radiographs can I'e ly 

 made of the heart when tht- 

 X-ra\' tube is placed no less 

 than two metres Ironi the plate, 

 as stiowu ill the ilhistration 

 accomi>an\ iiig the Inst part oi 

 this article. Owing to the 

 great distance of the tube, the 

 si/re of the shadow of the heart 

 is \er\- nearl\- the same as that 

 of the heart itself, and it is 

 the best method at our disposal 

 for accurately determining the 

 dimensions of that organ. 

 Changes in these dimensions 

 can be detected by making ex- 

 aminations at intervals. This 

 hv no means exhausts the list 

 of applications of the X-rays in 

 the diagnosis of disorders of 

 mankind, but enough has been said to show how much 

 progress has been made, ami the science is 1)\' no 

 means at a standstill. Improvements in methods and 

 in personal skill are being introduced every day, and 

 scarceh- a month [Kisses that does not give us some- 

 thing new in the way of impro\ed appliances. 



It was comparatively soon after the discovery of 

 the X-rays that some investigators began to employ 

 the radiation for purposes of treatment. They were 

 led to do this from the good results tliat were being- 

 obtained with the ultra-\iolet rays, and from the 

 fact that mam .\-ra\' workers had begun to suffer 

 from a form of dermatitis, which was rightly 

 attributed to the influence of the X-rays themselves. 

 It was at this stage that the foundations were laiil 

 for the immense amount of suffering that has been 

 endured b\- main" of the ])ioneers of X-ray work. 

 mam of whom still continue to suffer in one \\a\ or 

 other, ill spite of the fact that the\' haxc taken e\ery 

 possible precaution since the first attack ot the 



scientific as that of giving 

 ordinar\- drugs. We have no 



FiGi'Ri-: 



incurred bv those who are working with them more 

 or less continuously: there is not the slightest 

 danger to an\- one w ho undergoes an examination or 

 a course of treatment b\' the .X-rays, so long as the 

 one who is a recognised expert in 

 such matters. 



It ma^• be taken as an axiom 

 that am" agent that is capable 

 of doing so much harm as this 

 can also be made to do a great 

 deal of goo(l. if onlv its powers 

 ari_' propirK controlled and 

 directed into the right channels. 

 The ijreat trouble m adminis- 



tering these ra\s therapeutically 

 was that of know ing how large 

 or bow small a dose was being 

 gi\'en, and even at the present 

 time the methods at our disposal 

 are not anvthing like so simple 

 an(' 



s. 

 ]{ satisfactory method of ascer- 

 taining the exact strength of 

 radiation the patient is getting 

 at am' gi\'cn moiiK'nt : our 

 methods will oiiK' tell us how 

 r much has been gi\'en. and that 

 rather crudeh'. The means 

 mostiv eniplo\'ed are sufficienth' 

 accurate in the hands (jf one 

 who has had a considerable 

 exi)erience of the work, and 

 who has become more or less 

 familiar with the vagaries of 

 the X-ra\' tube. The day is 

 not \'et that the novice can 

 dip into this work without 

 running considerable risk. 



When the jdatino-cjanide 

 of barium is exposed for a 

 certain time to the influence of the X-ra^•s it turns 

 tnim its usual greenish-\'ell<iw tint to that of a 

 light orange. This material is spread upon stiff 

 paper and cut into small circular pastilles. The 

 X-ra\' tube is enclosed in a ray-proof shield, from 



y /;. Saui/as Electrical Cc>. 



Sanax Break in Section. 



which the ravs can escape only bv an opening made 

 tor the purpose, the size and shape of which can be 

 altered to suit an\' ordinarx' conditions. The pastille 

 is held in a clip exacth' half the distance between 

 the source of the ra\'s and the area to be treated, 

 and is so arranged that it can be removed for 

 examination from time to time. With each set of 

 pastilles is supplied a standard tint, to which the 

 pastille luust change before the ordinary full dose is 

 given. This is, in outline, the method in use at the 

 present time by the majority of radiologists. It is. 



othe 



r 



dermatitis. The dan;. 



fr 



thes 



se ra\'s is onl\' 



adniittedly, a crude one when judged by 

 standards of measurement, but in the hands of the 

 expert it gi\'es very good results. The arrange- 

 ment is shown on page 498 of the previous article 

 (" Kxo\Vl,l-:i>('.K,"\'olume XXXIII. December.lOlO), 



