ORIGIN OF SPECIES. 3II 



As I have pointed out, there is not at present evidence to show the origin 

 of any heritable variations in the soma. Moreover, I have shown that in 

 these beetles we can get new permanent variations by stimulating the germ 

 cells, and in no other way. The question is one for direct experimentation, 

 and not for the plausible arrangement of paleontological evidence. That the 

 Lamarckian factor could explain the phenomenon of evolution all admit, 

 could the fundamental assumption be established even in one single case. 

 Cope, of all the neo-Lamarckians, undoubtedly saw most clearly the real 

 issue and its results. Thus he writes : 



It is evident that evolutionists are reaching greater harmony of opinion on the ques- 

 tion of inheritance. In fact, the discussion is sometimes a logomachy dependent on 

 the significance which one attaches to the term "acquired characters." Thus Von Rath 

 remarks : "There is nothing in the way of the opinion that by the continued working of 

 such external influences and stimuli the molecular structure of the germ-plasm also 

 experiences a change which can lead to a transmission of transformations. Above all, 

 it ought not to be forgotten in this case that somatic cells are in no way the first to be 

 modified by the stimulus, and that then, by some sort of unexplained process (pan- 

 genesis or intracellular pangenesis), this stimulus is transmitted gradually by these 

 cells to the plasma of the germ-cells. The influence on the germ plasm is rather a 

 direct one, and if by continued influence a transformation of the structure of this plasm 

 takes place and transmission occurs, we have then simply a transmission of blastogenic, 

 and by no means of somatogenic characters, and therein is not the slightest admission 

 of the transmission of acquired characters. 



This paragraph contains an admission of the doctrine of diplogenesis, and does not 

 regard the phenomena as including a transmission of acquired characters. Nevertheless 

 the stimuli traverse the soma in order to reach the germ-plasma. Such an energy is 

 evidently, then, not of blastogenic origin, although it is such in its effects. Moreover, 

 Von Rath omits to mention the fact that in traversing the soma the stimulus frequently, 

 if not always, produces effects on the latter similar to those which it produces on the 

 germ plasma. I should call this process the inheritance of an acquired character, even 

 in the case where no corresponding modification appears in the soma, since the causative 

 energy is acquired by the soma, and is not derived from the existing germ plasma. 



The acceptance of Von Rath's view, and the assertion that because "causa- 

 tive energy traverses the soma" it is therefore acquired from the soma, is 

 largely a matter of definition of the terms used. The soma in this case is a 

 medium through which the stimulus passes, as through water, air, or earth ; 

 and while it is true that the "causative energy" is not derived from the exist- 

 ing germ plasm, neither is it derived from the soma, nor acquired by the soma, 

 but both soma and germ respond to the only stimuli which they can ever 

 experience those which are primarily external. After all, it would seem 

 that the question really comes down to a play upon words. The only ques- 

 tion is Can the effects of a stimulus which produces only a somatic variation, 

 as in the pupa in Poulton's experiments, or the beetles in the experiments of 

 the third chapter, be later transferred to the germ plasm? Only experimental 

 investigation can answer this question, and at present all the data give a 



