202 Cc. M. CHILD 
ter and consists in a variety of both compensatory and trans- 
formatory processes, but when an increment in all of these proc- 
esses occurs,.the change is quantitative in character and when it 
constitutes a process or part of a process of equilibration we are 
justified in calling it a compensation. 
It is of course evident that a classification of regulatory processes 
must finally become identical with the classification of processes 
occurring in the organism, for, as I have pointed out above, the 
regulations are not a peculiar form of organic activity ; they repre- 
sent merely the equilibrations resulting from the existence of physi- 
ological correlation between parts. But we shall probably always 
have occasion to refer to the organism, the system, as a whole 
undergoing equilibration or, relatively speaking, in equilibrium, 
consequeatly some means of distinguishing between the different 
methods of equilibration is useful. This is the chief significance 
which any classification of the regulations can possess. 
b. Regulatory compensation. Several different types of compen- 
sation can be distinguished, though they do not of course in most 
cases exist in nature or even in experiment apart from other 
processes. The following divisions under this head are suggested: 
Incremental compensation: The system shows an increment 
as compared with that previously existing. 
Decremental compensation: the system shows a decrement as 
compared with that previously existing. 
Reversional compensation: an increment or a decrement in 
some part of the system, induced by some external factor is 
correlatively more or less completely eliminated and the system 
approaches its previous condition. 
Alterative compensation: an increment or decrement in one 
part produces change in the opposite direction in another or in 
others, so that the proportional relations in the system differ from 
those previously existing. 
The first step in all compensations is of course a change in some 
part (a) induced by some factor external to the system. What 
particular form of compensation shall occur depends upon the 
degree of the change in the part and upon the character of the 
correlation existing betweea it and other parts (b,c, d—n). If for 
