28 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



equivocal nature of the results of experiment, warn us 

 that it may very well be a factor in transformism. And, 

 above all, one feels that the whole question of the nature 

 of the process of evolution turns upon the formulation of 

 a theory of heredity. 



It is probably safe to say that the only such theory 

 which we need consider is that of Weismann. Let us 

 admit that the central idea of this hypothesis — that of 

 the continuity of the germinal substance — is, generally 

 speaking, an eminently sound one. The species, rather 

 than the individual, is truly the organism. The germinal 

 substance does not act. Secluded from the environment, 

 the vicissitudes of the latter do not (in general) affect it. 

 It must grow, and in that respect must come into relation 

 with an environment, but the soma makes this environ- 

 ment inasmuch as body after body converts so much of 

 its medium as is necessary into an internal germinal 

 environment unchanging throughout generation after 

 generation. But variations in the soma reflect and 

 magnify variations in the germ. How then do the latter 

 arise? We trace them back to the time when the 

 distinction between soma and germ did not exist and 

 when the organism, being both soma and germ at the 

 same time, acted upon its environment and was impressed 

 by it. The individuals composing a metazean species 

 contain a germplasm of multiple origin, and consisting 

 of very numerous elements. Variability arises from the 

 permutations and combinations of these elements brought 

 about by amphimixis.* 



This hypothesis is so simple and clear that at first 



we hardly hesitate to accept it. But its application to 



the results of experiment so robs it of this pristine 



simplicity that we begin to doubt its truth. We see that 



* We admit the logical strength of Weismann' s later hypothesis 

 of germinal selection. But the difficulties arising on analysis of this 

 conception are very formidable. 



