VITAL FUNCTIONS. 83 



material." It is obvious, then, that there is something in 

 the so-called " chemical " processes of the plant over and 

 above ordinary chemical action as known to us ; and that 

 something, in our ignorance of its nature, we may still call 

 "vital," even though we believe that it will ultimately be 

 shown to be nothing more than a modification of some 

 physical force. 



