PROGRESS IN ANATOMY 



fevers, or whenever it falls below, as at the 

 approach of death. From Homer downward, 

 the breath of man suggested itself as the vital 

 principle or its vehicle. How about its re- 

 lation to the body's heat? This perplexing 

 question brought great confusion.®* Air seems 

 both hot and cold; and any one can blow hot 

 or cold with the same mouth. Was the vital 

 and necessary breathing of the air, in and 

 out, a cooling or a warming of the body? 

 Opinions wavered and contradicted each other 

 for centuries. Apparently — the whole matter 

 is exceedingly obscure — the early physicists 

 with Hippocrates were ranged on the side of 

 warming, and Aristotle with his great influence 

 on the cooling side. Nearly two thousand 

 years later, Harvey remained perplexed. 

 After his death, the search was carried on more 

 vigorously for some needed and explanatory 

 process analogous to the burning of combust- 

 ible things, in fine, for a process of combustion. 

 The goal was reached through the discovery of 

 oxygen and the slow-won knowledge of its 

 functions in the human economy. 



[97] 



