i28 Darwin, and after Darwin. 



purely gratuitous, there is no small amount of 

 evidence to the contrary or evidence which seems 

 to prove that a similar transmission occurs likewise 

 in the higher plants. And no doubt many additional 

 cases might be advanced by any one who is well 

 read in the literature of economic botany. 



It appears to me that the only answer to such cases 

 would be furnished by supposing that the heredi- 

 tary changes are due to an alteration of the residual 

 "germ-plasm" in the wild seed, when this is first 

 exposed to the changed conditions of life, due to 

 its growth in a strange kind of soil e. g. while ger- 

 minating in an unusual kind of earth for producing the 

 first generation. But this would be going a long 

 way to save an hypothesis. In case, however, it 

 should now be suggested, I may remark that it 

 would be negatived by the following facts l . 



In the first place, an endless number of cases might 

 be quoted where somatogenetic changes thus pro- 

 duced by changed conditions of life are not hereditary. 

 Therefore, in all these cases it is certainly not the 

 " germ-plasm " that is affected. In other words, there 

 can be no question that somatogenetic changes of the 

 kinds above mentioned do very readily admit of being 

 produced in the first generation by changes of soil, 

 altitude, &c. And that somatogenetic changes thus 

 produced should not always or even generally 

 prove themselves to be hereditary from the first 

 moment of their occurrence, is no more than any theory 



1 Since the above was written Professor Weismann has advanced, in 

 The Germ-plasm, a suggestion very similar to this. It is sufficient here 

 to remark, that nearly all the facts and considerations which ensue in 

 the present chapter are applicable to his suggestion, the essence of which 

 is anticipated in the above paragraph. 



