THE THEORY OF DESCENT 291 



that relates to the so-called types as such and the degree of 

 complication in these types, both of which (types and degree 

 of complication) are independent of histological adaptation, 

 and adaptedness. 



What then do we know about any facts that might be 

 said to bear on this problem ? We have stated already 

 at the end of our chapter devoted to the analysis of heredity 

 that what we actually know about any deviation of inherit- 

 ance proper, that is, about congenital differences between 

 the parents and the offspring, relating to mere tectonics, 

 is practically nothing : indeed, there are at our disposal 

 only the few facts observed by de Vries or derived from 

 the experience of horticulturalists and breeders. We may 

 admit that these facts at least prove the possibility l of 

 a discontinuous variation, that is of " mutation," following 

 certain lines of tectonics and leading to constant results ; 

 but everything else, that is everything about a real theory 

 of phylogeny, must be left to the taste of each author who 

 writes on the theory of the Living. You may call that a 

 very unscientific state of affairs, but no other is possible. 



And, in fact, it has been admitted by almost all who 

 have dealt with transformism without prepossessions that 

 such is the state of affairs. Lamarck himself, as we have 

 mentioned already, was not blind to the fact that a sort of 

 organisatory law must be at the base of all transformism, 

 and it is well known that hypothetical statements about 

 an original law of phylogeny have been attempted by 



1 But nothing more. All "mutations" hitherto observed in nature or 

 (comp. page 238, note 3) experimentally produced relate only to " varieties " 

 and not to " species." One could hardly say that the recent investigations 

 about the production of mutations by external means have strengthened 

 their importance for the general theory of transformism. 



