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.” 2° 
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. 
**Delage: L’hérédité et les grands problémes de la biologie 
générale. P. 174. 
