Applications of Organic Selection 177 



support to two different accommodations, or as cooperating 

 factors in them, varies in both directions, and so divergent 

 congenital characters are evolved. 



Or, again, two or more different accommodations may 

 subserve the same utility, and thus conserve different lines 

 of variation. To escape floods, for example, some indi- 

 viduals of a species may learn to climb trees, while others 

 learn to swim. This has been recognized in Gulick's 

 ' Change of Habits' considered as a cause of segregation, 

 and thus also of divergent evolution. 1 



(4) In cases of apparent permanent influence, upon 

 a stock, of temporary changes of environment, as in 

 transplantation : the direction of variation seems to be 

 changed by the temporary environment, when there is 

 really only the temporary ' indirect ' selection of varia- 

 tions appropriate to the changed environment. For ex- 

 ample, it is possible that plants undergo quick changes 

 by indirect selection when transplanted, the effects of 

 this selection of variations continuing a longer or shorter 

 period after returning to the original conditions of life, espe- 

 cially when the original environment does not demand their 

 prompt weeding out. This is one of the cases frequently 

 cited as favouring the hypothesis of Lamarckian inheri- 

 tance. 



The matter may be made clear by concrete illustra- 

 tions. The point is made by Lamarckians, especially by 

 botanists, based upon alleged facts, that modifications 

 which are produced in plants when they are transplanted 

 into new conditions are retained in greater or less degree 

 by the descendants when they are re-transferred back to 



1 The implications of this position, as well as of the two preceding points 

 (i and 2) are brought out in the following chapter. 



N 



