THE NERVOUS SYSTEM 33 



eral principles of physics and chemistry, and 

 are, therefore, grounds for opposition to the 

 opinion just alluded to. However, in consid- 

 ering this opposition it must not be forgotten 

 that these sciences are still in process of ac- 

 tive growth, and that what we regard as their 

 general principles to-day are principles devel- 

 oped chiefly from a study of inorganic na- 

 ture. In only a most tentative way have these 

 sciences begun to touch matter and energy as 

 exhibited in organisms. How their principles 

 will be modified when they really begin a suc- 

 cessful attack on living beings remains to be 

 seen, but that these principles will be modified 

 there can be not the least doubt. Then will be 

 the time to raise the question of the nature 

 of the voluntary act and other such problems if, 

 indeed, these problems really remain serious 

 in the light of the new knowledge, for often 

 what seems to be a perplexing question to-day 

 becomes insignificant to-morrow. Who con- 

 cerns himself now with the number of angels 

 that can stand on the point of a needle ? 



But I cannot leave this matter of memory 

 and the voluntary operations without consid- 

 ering somewhat further the part of the human 

 nervous system in which these functions occur. 



