24 BIOLOGICAL ASPECTS OF HUMAN PROBLEMS 



culty have urged that we must call in to our aid the 

 supposition that there is something analogous to a 

 form of intelligence, which regulates and controls 

 growth and life processes generally. Views of this 

 sort signify a return to a vitalistic type of doctrine, 

 and differ from older views mainly in the definite- 

 ness of the evidence that seems to compel their 

 adoption. They may properly be thought of as 

 constituting a " neo-vitalistic " teaching. But this 

 teaching, like all vitalistic doctrines, impresses us 

 with its unsubstantial or negative quality. It re- 

 minds us of the words put by Goethe into the mouth 

 of Mephistopheles, "Und gerade da wo die Begriffe 

 fehlen stellt sich zur rechten Zeit ein Wort herein." 

 What should be the attitude of those who seek the 

 truth regarding this neo-vitalistic doctrine this 

 modern and legitimate representative of an idea that 

 has occupied the attention of thinking men in every 

 period of history? The question whether the ani- 

 mal organism is merely a machine like an engine 

 or clock, dependent on physicochemical forces, or 

 is " animated" by a specific "vital principle" or 

 "vital force" is surely one of the most momentous 

 in its relation to man's place in nature. In our brief 

 review of the resemblances and differences between 

 the animal mechanism and the machine of human 

 make, we have been brought face to face with two 

 incontrovertible facts of the largest significance. 

 On the one hand, it is quite clear that the body is a 

 machine. Not only does it make use of the simple 



