190 Cc. M. CHILD 
So far as it enables the organism to persist, it may be of advantage, 
and I see no escape from Roux’s argument (Roux, 795, I, p. 145, 
154, etc.),that systems possessing such reactions will persist longer 
than others. But not all regulatory processes are of advantage 
to the organism and many of them, e. g., the so-called axial heter- 
morphoses, lead to its destruction or its disruption, but they are 
no less regulations because of this result. 
According to Driesch (’01, p. 92), ‘‘ Regulation ist ein am leben- 
den Organismus geschender Vorgang oder die Anderung eines sol- 
chen Vorgangs, durch welchen oder durch welche eine irgendwie 
gesetzte Stdrung seines vorher bestandenen ‘normalen’ Zustands 
ganz oder teilweise, direkt oder indirekt, kompensirt und so der 
‘normale’ Zustand oder wenigstens eine Annadherung an ihn wie- 
der herbeigefithrt wird.” 
If we accept this definition, then the processes which do not 
constitute a return or approach to the previously existing ‘normal’ 
condition are not regulations. This normal condition is nothing 
but the condition which corresponds to a certain complex of exter- 
nal factors or to changes within certain limits. Under changed 
conditions a new equilibrium, not the old, is established. In 
short, if we accept such a definition, we not only exclude many 
processes which are as truly regulatory as any, but we are forced 
to assume the existence of an entelechy or other similar principle 
to account for the ‘normal’ condition and its maintenance. 
Regulatory processes are determined in character and direction 
by the nature of the organism, on the one hand, and the nature and 
amount of the external change, on the other. Under the given 
conditions, the organism or part is capable of doing only the one 
thing; under other conditions, or with a different constitution, the 
regulation may occur in a different manner and may often lead 
toa different result. In Planaria, for example, the course and result 
of regulation differ according to the size of the piece, the region 
of the body from which it is taken, the temperature, the nutritive 
conditions and other factors. To say that the pieces always 
produce a whole under all these conditions means but little, for 
the wholes which they produce are not alike. In plants the charac- 
ter of the external change often plays a very large part in deter- 
