EXPERIMENTAL MORPHOGENESIS 161 



to the whole, but will be regulated afterwards by processes 

 of growth. Thus, indeed, there is a sort of equifinality of 

 restitution : one starting-point, one end, but three different 

 means and ways. 



It would, of course, contradict the principle of uni- 

 vocality, as we shall see more fully later on, to assume 

 that there actually are different ways of regulation whilst 

 all the conditions and stimuli are the same. We are 

 obliged to assume, on the contrary, that this is not the 

 case, that there are certain differences in the constellation, 

 say of the general conditions of age or of metabolism, 

 which are responsible for any given individual choosing 

 one process of restitution instead of another ; but even then 

 the phenomenon of equifinality remains very striking. 



It has long been known that restitution in general does 

 not always follow the same lines of morphogenesis as 

 are taken by ontogeny, and it was this feature that once 

 led Eoux to point out that the adult forms of organisms 

 seem to be more constant than their modes of origin. But, 

 comparing ontogeny with restitution in general, we see that 

 only the ends are the same, not the points of starting ; 

 the latter are normal or non-typical in ontogeny, atypical in 

 restitution. In the new discoveries of an equifinality of 

 restitutions we have the same starting-point, which is 

 decidedly non- typical but atypical, i.e. dependent on our 

 arbitrary choice, leading by different ways always to the 

 same end. 



There may be many who will regard the fact of 

 equifinality as a proof of vitalism. I should not like 

 to argue in this easy way; I indeed prefer to include 

 part of the phenomena of equifinality in our first proof 



ii 



