PHYSICAL andLITERARY. 251 



the aneurifmal cyfls generally grow firm- 

 ly to the bone, and the force of the 

 blood ading continually agamfl the fide? 

 of the artery, while it is refifted by the 

 firm bone on the other fide, wafles away 

 that part of the cyfl, gives rife to ob- 

 ftrucSlions and fuppiirations of the bone, 

 or its membranes, lays bare the bone, 

 and renders it carious, as we find by ex- 

 amining many cafes of aneurifms reli- 

 ted by authors *. Frequently the pul- 

 fation of the blood againft the fides of the 

 cyfl, and the prefTure of the cyfl again fc 

 the bone, give rife to obriru(5tions, and 

 iConfequent fuppurations, and render the 



hone 



* See a cafe where tTie ribs were rougli and carious 

 In Manget. Bibliothec, Chirurgic, vol, i. pag. 93. frora 

 Ephemer. German, cent. i. and 2. The end of the 

 clavicle was laid bare, and rough and carious, in the 

 cafe related by Le Dran. Obf, Chir. vol, i. obf. 40. I 

 felt the vertebrae rough and cariotis when I introduced 

 my finger into the dilated aorta 01 a man who died 

 Irom the burfting of an aneurifoi in St George's Hofpitai, 

 in the year 1752; this cafe is related by Dr Hunter in 

 the firft volume of Medical Obfervailons and Inquiries, 

 publifhed at London. Many raoie fuch cafes might be 

 quoted. 



