VARIOUS THEORIES. 625 



distinct from all the other powers in nature;" 

 while Dr. C. Holland adopts the hypothesis of 

 Bichat, Richerand, Magendie, Prichard, Flet- 

 cher, cum multis aliis, that " life is not a simple 

 principle, but the result of compound principles 

 and actions, pervading and common to every part 

 of nature." (Laws of Organic and Animal Life, 

 p. 355.) Alas ! the contradictions and mysteries 

 of science are scarcely less perplexing and pre- 

 judicial to the interests of mankind, than those of 

 metaphysics and scholastic divinity. 



" For 'tis not only individual minds 

 That habit tinctures, or that interest blinds ; 

 Whole nations fool'd by falsehood, fear, or pride, 

 Their ostrich heads in self illusion hide." 



THOMAS MOORE. 



The earliest theory of digestion that has come 

 down to us is that of Hippocrates, who regarded 

 it as a species of concoction analogous to the 

 ripening of fruits by solar heat. The same view 

 was adopted by Galen, and taught by nearly all 

 his successors, down to the time of Paracelsus 

 and Van Helmont, who referred it to the agency 

 of an acid liquor, under the control of the Archeus, 

 which was supposed to be endowed with intelli- 

 gence, to direct the stomach when to allow its 

 contents to pass into the duodenum, to give the 

 alarm and cause it to expel whatever is noxious, 

 and to preside over all those actions of the living- 

 body that constitute the vis conservatrix nature. 



