SECTION XIV 



DISEASES OF THE BLOOD AND BLOOD 



VESSELS 



Aneurysms 



ANEURYSMS are true and false, the former con- 

 sists of a dilatation of the walls of ah artery, 

 which is filled with blood, in the latter all the coats 

 are ruptured but the blood is retained by the sur- 

 rounding tissues. 



Symptoms. — The general symptoms, of aneurysms 

 ar6: The formation of a pulsating tumor; a peculiar 

 bruit heard over the swelling and pressure symp- 

 toms, consisting of pain and paralysis from pressure 

 on nerves and absorption of contiguous parts. The 

 aorta is the artery most commonly affected. 



Treatment. — There is no effectual treatment, but 

 rest and avoidance of excitement or exertion may 

 defer rupture and death. In rare cases, where only 

 a small artery is affected and the collateral circula- 

 tion good, the aneurysm should be removed by first 

 ligating the artery above and below and then ex- 

 cising it. 



Hematozoa 



The commonest and most important hematozoa 

 in our patients are the Filaria immitis, the Strongy- 

 lus vasorum, and the Spirotera sanguinolenta. 



Filari Immitis 



This parasite is found in localities rich in marshes 

 and surface water. It is supposed, though not defi- 

 nitely proved, that such stagnant waters become 

 infected by the embryos of the parasite by means of 



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