S28 LECTURE V. 



exerted, determining the blood into one set 

 of vessels in preference to another. How 

 then can we account for the vehement hae- 

 morrhages which take place from inflamed 

 arteries, unless we admit vessels of magni- 

 tude to possess vital activity ? Do we not 

 know that an hEemorrhamc action is a natu- 

 ral phasnomenon in some parts of the body, 

 that arteries occasionally pour the blood so 

 impetuously into the corpus cavernosum 

 and spongiosum, as suddenly and forcibly 

 to distend them ? 



I can scarcely believe that if an anato- 

 mist were injecting the principal artery of 

 the dura mater, and had burst its trunk, 

 he could, with his utmost efforts, expel so 

 large a quantity of injection, and compress 

 the brain to the degree that we sometimes 

 find it to be by blood, when that vessel is 

 torn and irritated by injury. Yet the same 

 vessel does not bleed when exposed. Can we 

 account for such facts from the actions of 

 the heart alone ? How also, I would ask, am 

 I to account for the vehement throbbing of 

 all the large arteries of the arm, even as far 



