74 NATIONAL TRENDS IN BIOLOGY 



all respects so disposes them that the latent being comes 

 to full expression. The organism is primary, not secon- 

 dary ; it is an individual, not by virtue of the cooperation 

 of countless lesser individualities, but an individual that 

 produces these lesser individualities on which its full 

 expression depends. The persistence of organization is a 

 primary law of embryonic development." 



But it was left for William E. Ritter to treat the whole 

 theory in a most comprehensive and exhaustive manner 

 in his two volumes entitled, The Unity of the Organism 

 (1919). I have, therefore, asked Professor Ritter to put 

 into as few words as possible a statement of the theory 

 itself and what actually brought it into being. This is 

 what he says : 



"There is no doubt that the theory has been in the 

 world from the time of Aristotle at least. How much 

 longer I do not know. When this Greek pointed out that 

 any object, a couch for example, has certain attributes of 

 its very own and hence cannot be interpreted on the 

 basis of the attributes of any other object, even though 

 these be those of which the object in question is com- 

 posed, he simply called attention to an item in the mental 

 technique employed by every working naturalist, no mat- 

 ter what his field. It is of prime historic importance, I 

 think, to distinguish between Aristotle the naturalist and 

 Aristotle the metaphysician. 



"My own first arresting glimpse of the knowledge- 

 getting principle here involved came, as I recall, from 

 noticing that when the materialists (really elemental ists) 



