PHYSICAL AND LITERARY. 2j/ 



nefs of tlie arteries. In the one which 

 had burft and degenerated into the 7nixed 

 kind, the fides of the cyft were thicker and 

 firmer j in general, all aneurifms in this 

 Hate, and all the fiife ones, like other inr 

 cyfted tumours, have their fides thick in 

 proportion to their fize. 



II. Aneurisms, which follow wounds, 

 Blov/s, violent ftrainings of the body, or 

 ©ther fuch accidents, probably often take 

 their rife from a rupture of fome of 

 the proper coats, or of the cellular 

 fubftance which conneds them to the 

 neighbouring parts, and ferves by way 

 of an outer covering, and from a dilata- 

 tion of thofe coats, or part of coats 

 which remain entire; for Dr Nichols' air 

 ledges, in the Philofophical Tranfadlions, 

 No. 402. that if air be blown forcibly 

 into the pulmonary artery, the coat 

 called mufcular will yield and burft, 

 and the external be dilated into a cyft j 

 and, Dr Hailer^, in a memoir which he 



publillied 



* See Aft. Societat. reg. Gottingen. ifss » ^^'^ ^^'' 

 SBoire l. Surls Mouvcoieat de B^n^. page lo. ilS^ 



