ANEURISM. 71 
ANEURISM. 
An enlargement of a part of an artery from the bursting of its inner and middle 
coats is termed aneurism. The outer, fibrous coat stretching, a sack is formed, 
in which a portion of the blood coagulates solidly. This may happen on any artery, 
yet the accident is very rare in dogs. In consequence of disease, the inner coats 
of the affected artery may become weakened, when they rupture more easily ; 
but in most cases the cause of their giving way is a sudden and great strain, such 
as may occur from a fall from a considerable height, or be the result of intense 
effort, as a long, hard run. 
Aneurism is but rarely detected during life. Its progress is slow, occupying 
generally several years before its fatal end; and but little can be done to stay 
its progress. 
