212 TRA.VSMISSION OF ACQUIRED CHARACTEI:.; 



are blood-relations, derived from a common ancestor. Are 

 they not due to the environmental differences ? In some way, 

 surely, the organismal differences are causally correlated with the 

 environmental differences, and it is granted by all that pecu- 

 liarities of climate induce changes in the nutrition, respiration, 

 circulation, and so on. If so, the germ-plasm may be affected 

 and variations may be provoked, some of which are adaptive. 

 But the result of these variations may be something different 

 from and much more profitable than the modifications directly 

 induced. They may be expressed in relation to quite different 

 organs. Thus it seems quite unnecessary to believe in the trans- 

 mission of climatic modifications as such, or in any representa- 

 tive degree. Moreover, we must never forget that the active 

 organism must be credited with the power of seeking out en- 

 vironments which suit its inborn nature — variations included. 



Plants in New Environment. — Much has been made of the 

 changes which follow a radical change of environment. When 

 a plant is transferred to a new soil and climate it may undergo 

 a very marked change of habit ; its leaves may become hairy, 

 its stem woody, its branches drooping. " These," Herbert 

 Spencer said, " are modifications of structure consequent on 

 modifications of function that have been produced by modifica- 

 tions in the actions of external forces. And as these modifications 

 reappear in succeeding generations, we have, in them, examples 

 of functionally established variations that are hereditarily trans- 

 mitted." But this is a non-sequitur, since the modifications 

 may reappear merely because they are re-impressed directly on 

 each successive generation. It is Misunderstanding IV. 



At the same time it should be noted that radical change of 

 environment may induce germinal variations or mutations 

 which breed true. These must be distinguished from modifica- 

 tions, as already explained, since we cannot interpret them 

 physiologically as the direct somatic results of the environmental 

 change. 



