A HISTORY OF SCIENCE 



size. Puzzled as to how this could be, and suspecting 

 that in some way his ligature around the artery had 

 not been effective, he ordered the deer killed, and on 

 examination was astonished to find that while his liga- 

 ture had completely shut off the blood -supply from 

 the source of that carotid artery, the smaller arteries 

 had become enlarged so as to supply the antler with 

 blood as well as ever, only by a different route. 



Hunter soon had a chance to make a practical ap- 

 plication of the knowledge thus acquired. This was 

 a case of popliteal aneurism, operations for which had 

 heretofore proved pretty uniformly fatal. An aneur- 

 ism, as is generally understood, is an enlargement of a 

 certain part of an artery, this enlargement sometimes 

 becoming of enormous size, full of palpitating blood, 

 and likely to rupture with fatal results at any time. 

 If by any means the blood can be allowed to remain 

 quiet for even a few hours in this aneurism it will form 

 a clot, contract, and finally be absorbed and disap- 

 pear without any evil results. The problem of keep- 

 ing the blood quiet, with the heart continually driving 

 it through the vessel, is not a simple one, and in Hun- 

 ter's time was considered so insurmountable that some 

 surgeons advocated amputation of any member having 

 an aneurism, while others cut down upon the tumor 

 itself and attempted to tie off the artery above and 

 below. The first of these operations maimed the pa- 

 tient for life, while the second was likely to prove 

 fatal. 



In pondering over what he had learned about collat- 

 eral circulation and the time required for it to become 

 fully established, Hunter conceived the idea that if 



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