322 BIOLOGICAL LECTURES. 



organism ? What vibration could there be between germ and 

 passive structures, such as shell configurations ? Could an 

 indentation, groove, ridge, or protuberance forced upon a shell 

 by environmental action be at the same time wrought into the 

 germs in such a definite way as to reappear in the offspring 

 without the aid of the same environmental causes ? Or could 

 the repetition of the same environmental action on a long line 

 of parents gradually modify the germs in the same direction ? 

 In whatever way we turn the question, we are confronted with 

 the same miracle of preformation. The character arises in the 

 parent organism by epigenesis, but it is thrown back on the germ, 

 nobody knoivs or can conceive how, in such a way that it becomes 

 a preformation capable of unfolding without the aid of its epi- 

 genetic causes. 



On the other hand, the hypothesis that all hereditary 

 characters in organisms exclusively gamogenetic originate in 

 spontaneous or induced (by direct action of environment) germ 

 variations, appeals only to known facts and principles, and 

 provides for the same amount of preformation as before with- 

 out any miraculous transfer of characters from one organism 

 to another. We know that germ variations are transmissible ; 

 we do not know that individually acquired modifications can be 

 transferred to germs ; we know the principle of selection to be 

 rational and verifiable ; we know of no substitute for it. 



THE GENETIC STANDPOINT IN THE STUDY OF INSTINCT. 

 a. The Genealogical History Neglected. 



The problem of psychogenesis requires a more definite 

 genetic standpoint than that of general evolution. It is not 

 enough to recognize that instincts have had a natural origin ; 

 for the fact of their connected genealogical history is of para- 

 mount importance. From the standpoint of evolution as held 

 by Romanes and others, instincts are too often viewed as dis- 

 connected phenomena of independent origin. The special and 

 more superficial characteristics have been emphasized to the 

 exclusion of the more fundamental phylogenetic characters. 



