212 Cc. M. CHILD 
expressed himself in somewhat similar terms, but he finds neverthe- 
less, as already noted above, that the ‘Individualitét der Zuord- 
nung’ between agent and effect cannot be accounted for on a 
physico-chemical basis and therefore regards it as a new ‘proof’ 
of the autonomy of vital processes. 
3. The process of equilibration in reconstitution 
The process of equilibration in reconstitution differs in many 
details in different cases, but it possesses certain more or less char- 
acteristic features, and it is desired to call attention briefly to 
some of these. The change in physiological correlation is the inter- 
nal factor which has disturbed the preéxisting condition, whatever 
that may have been. This change may or may not lead to equili- 
bration of the living organism. If the change be great, if the other 
parts possess but little capacity for altering their reactions, it 
may lead to death. On the other hand, it may lead to reconstitu- 
tion in various ways according to conditions. 
Let us consider first the case where a part is removed and is 
formed again without any great changes in other parts, e.g., the 
‘regeneration’ of the posterior end of Planaria. 
In the absence of the correlative factors which originated in the 
part removed (a), certain regions (b) of the remaining ‘parts (b,c 
d ———n), which were before prevented by these correlative factors 
from reacting as their own constitution and the correlative factors 
from other parts would determine, now begin to react in this man- 
ner. In the region adjoining the part removed, 7.e., in the cells b, 
the correlative factors originating in the parts cd-—~—n are more or 
less similar in their effect to those which affected the part removed 
(a). So far as they are and remain similar, and so far as the con- 
stitution of b permits, this region will be forced by the correlative 
factors to react more or less in the manner of a, which is no longer 
present, and 6 will replace a more or less completely and more or 
less rapidly, according to conditions in the particular case®. If 
5 The formation of a new head in Planaria or a new hydranth in Tubularia isa 
somewhat different process from the formation of the proximal or posterior end. 
In these forms the anterior or distal region is physiologically dominant over parts 
