8 THE GERM -PLASM 



in the children, — a problem which is doubtless well worthy of 

 investigation, but which, at the same time, deals only with a 

 side issue of the processes of reproduction. How little I under- 

 rate the significance of amphigonic heredity, even in its theo- 

 retical relations, will be evident in a later part of this book, in 

 which I attempt to derive the existence of the germ-plasm from 

 the phenomena of this form of heredity : but to me it seems 

 dangerous to investigate heredity theoretically from the point 

 of view of amphigonic descent exclusively, because one has here 

 to deal with the most complex of all the phenomena, and the 

 main point may easily be overlooked in a mass of confusing 

 secondary considerations. Even Galton, in my opinion, allowed 

 himself to be too much influenced by this aspect of the ques- 

 tion. Excellent as are his later researches on the laws relating 

 to the blending of characters of the parents in the children, I 

 consider his theoretical deductions on the fundamental phe- 

 nomena of heredity unsatisfactory. The few hints that he gives 

 as to the cause of ontogeny seem to me by no means equal to 

 Darwin's simple but truly penetrating and accurate deductions. 

 It is quite conceivable that the phenomena of the blending of 

 the characters of the parents in the children would be the most 

 interesting to a statistician and anthropologist like Galton, but 

 they have kept him within the limited range of these phenomena, 

 and have prevented him from arriving at really general principles 

 and at a comprehensive theory of heredity. 



Galton has, however, the merit of having been the first to 

 deny the circulation of the gemmules, and, in connection with 

 this, to cast doubt upon the general validity of the doctrine of 

 the transmission of acquired modifications. He certainly be- 

 lieves the latter to be ' faintly heritable,' and assumes, in order 

 to explain this transmission, that no general ' circulation of the 

 gemmules ' takes place, but that each cell sets free some gern- 

 mules which get into the circulation and eventually penetrate 

 into the sexual elements. 



Galton's essay was published only a few years after the ap''' 

 pearance of Darwin's theory of pangenesis ; but it cannot b>^> 

 said that it exercised any influence on the subsequent develop S' 

 ment of the theory of heredity. Apparently it was not muc) 

 noticed even in England, and on the Continent it remainec]- 

 unknown for a long time. This must be my excuse for beingJB- 

 ignorant of the existence of this paper, and consequently for 



