240 PRINCIPLES OF PHYSIOLOGY 



will, get further into the molecular arena, and 

 be able to explain some of those phenomena, 

 which at present are so obscure. We need 

 not proclaim what we do not know, and assert 

 that all of these phenomena are in reality 

 physical, because this is simply begging the 

 question. There are phenomena, however, 

 which we may feel assured can never be so 

 explained. Those of a mental kind can never 

 be thus accounted for, and no metaphysical 

 subtleties, either from a materialistic or an 

 idealistic standpoint, will ever satisfy the 

 mind. How are we to give a physiological 

 explanation of human personality ? 



144. Progress in physiology can only be 

 made by a resolute investigation of all the vital, 

 physical, and chemical phenomena that occur 

 in living matter and in living beings. This must 

 be done by the methods followed by physiolo- 

 gists, with all the help they can receive from 

 the rapid accumulation of knowledge. At one 

 time anatomical, at other times histological, 

 considerations govern the science. The older 

 anatomists were content to display the organs 

 and to infer their functions. The cell theory 



