1 62 Studies in the Theory of Descent. 



many varying external influences can bring about 

 changes in an organism by direct action. That 

 these two transforming factors, together with 

 their correlatively induced changes, are competent 

 to produce all characters, howsoever insignificant, 

 has indeed been truly asserted, but has never yet 

 been proved. The solution of the problem, how- 

 ever, appeared to me to depend particularly on this 

 point. We are now no longer concerned in prov- 

 ing that a changing environment reacts upon the 

 organism this has already been shown but we 

 have to deal with the question whether every 

 change is the result of the action of the environ- 

 ment upon the organism. Were it possible to 

 trace all the forms of markings which occur, to 

 one of the known factors of species transforma- 

 tion, it could be thus shown that here at least an 

 " innate power of development " was of no effect ; 

 were this not possible, i. e. did there remain 

 residual markings which could not be explained, 

 then the notion of an " innate principle of de- 

 velopment " could not be at once entirely discoun- 

 tenanced. 



The attempt to solve this problem should com- 

 mence by the acquisition of a morphological 

 groundwork, so that the phyletic development of 

 the markings might by this means be represented 

 as far as possible. It cannot be stated with cer- 

 tainty, primd facie, whether some form of de- 

 velopment conformable to law is here to be found, 



