SEC. II THE AUTHOR'S EARLIER VIEWS 21 



tion, the earlier view of Darwin, afterwards abandoned by 

 that great naturalist himself, that every character occurring 

 in an organism must either be now useful, or must at some 

 time or other have been useful. I brought forward in opposi- 

 tion to this the great importance of indifferent characters. I 

 said then,^ at a time when the Darwinian principle of utility 

 still exclusively prevailed among zoologists in Germany : 

 (1) "From internal causes conditions of organisation may arise, 

 may as it were crystalise out, which are just as useful to the 

 organism as if they had been due to the struggle for existence. 

 In this case the claims of the principle of utility are accident- 

 ally satisfied by the results of evolution from internal causes, 

 and the importance of that principle remains therefore 

 undiminished. (2) From internal causes characters which 

 are indifferent for the success of the organism, and (3) even 

 harmful characters may arise. . . . But organisms burdened 

 with harmful characters can only maintain themselves, and only 

 transmit their peculiarities through future generations when 

 such characters are inconsiderable in comparison with the useful 

 ones also present, or when such characters stand in correlation 

 with others whose usefulness is greater than their harmfulness." 



With these words I already at that time (1874) assumed 

 as important agencies in the modification of species causes 

 independent of the Darwinian principle of utility. At the 

 same time I emphatically stated that it was self-evident that 

 no form could continue to exist which unconditionally 

 contradicted that principle. 



Instead of the expression " internal causes " I subsequently 

 employed " constitutional causes," in order to indicate that I 

 sought the causes of the modification of forms not in some 

 fundamental impulse corresponding to vital force, but rather 

 in physical and chemical processes depending on the material 

 composition of the body. 



^ Lacerta muralis ccerulea, 1874. 



