216 C. M. CHILD 
4. The complexity of reconstitution 
The process of reconstitution is not a simple process which can- 
not be analyzed, but rather an exceedingly complex one; in fact 
its complexity is of the same order and character as that of devel- 
opment. It consists of a series of compensations and transforma- 
tions in different parts of the system. It is only when we take into 
account the complexity of physiological correlation between parts 
and the almost infinite possibility of change and variety in this 
correlation that we have any hope of gaining an insight into the 
complex series of events. The specificity of correlation and reac- 
tion does not, as Driesch apparently believes (Driesch, ’09) con- 
stitute a physico-chemically insoluble problem except when we 
follow Driesch in ignoring the energy current as an equilibrating 
factor in the organism and as the efficient factor in construction of 
the visible and tangible characteristics. 'The energy current 
performs its work under specific conditions in each case and leads 
to a specific result. As soon as a specific condition arises in any 
part of the system, from whatever cause, it determines other speci- 
fic conditions in at least certain other parts. From the experi- 
ments on Planaria it is perfectly apparent that the cells at every 
level of the body posterior to the ganglia, are capable under cer- 
tain conditions of developing into a head, but under the usual 
conditions they are prevented from doing this because the cor- 
relative factors arising from the presence, 7. e., the activities, of a 
head determine their activities in another direction. As soon as 
the old head is eliminated from the system, those cells, which in 
consequence of their past correlation are most similar to it, be- 
gin at once to form a new head, provided the piece is not too small 
and as soon as this occurs it determines correlatively a variety 
of reactions in other cells. The same may be said of the reconsti- 
stitution of any part. The place where a particular part shall 
arise is determined by constitutional and correlative factors in 
the existing system—so far of course as external factors are not 
concerned—and as sooa as one such place is determined, it deter- 
mines others and so on. ‘Thus any case of reconstitution consists 
of a series of regulations, each of which determines others. This 
