48 Nature of the Formative Stimulus 



well, that after the cutting off of organs not yet in 

 function, for example of the testicle or of an infantile 

 ovary or several infantile milk glands, the other similar 

 organs underwent in their respective parts a proportionate 

 growth as though they would thus compensate for absent 

 parts. It would appear from this that the networks of 

 correlation belonging to each of these parts of like organs 

 must come off from a common principal branch in such 

 a way that the whole current of this branch prevented 

 from the usual division by the absence of one part of 

 the network would now discharge itself entirely into 

 the remaining organ. 



The hypothesis of the continuous circulation or the 

 continuous general distribution of nervous energy which 

 thus finds its support in certain special phenomena of 

 development, affords better than any other an explana- 

 tion for the fundamental process of every ontogeny, 

 which consists as Roux has very aptly said only in a 

 series of unequal localizations of growth. 



"A given region grows," writes Delage, "while the 

 neighboring parts by which it is surrounded, grow much 

 less or not at all. This part must necessarily then project 

 outward or become invaginated and form a cavity. But 

 at a given moment growth ceases in this place and goes 

 over to another place, and the same phenomenon is now 

 repeated at this new place." 25 



The morphological means which ontogeny employs is 

 then always the same, always of the same identical nature 

 even when the tissues already partially differentiated 

 commence to differ from one another in their most 

 essential properties. 



25 Delage: L'heredite et les grands problemes de la biologic 

 generate. P. 174. 



