196 EVOLUTION 



in some cases at least, from reaching even the 

 germ-cells in their recesses ? 



In this connection, it is only just to recall 

 the remarkable speculative insight of the late 

 Samuel Butler, that most convinced and 

 argumentative of Lamarckians, who, more or 

 less simultaneously with Hering in Prague, 

 propounded a generation ago much the same 

 doctrine of " Organic Memory," as that which 

 we now owe to Semon. Haeckel too has 

 expounded much the same doctrine; and no 

 doubt in increasingly clarified form it must 

 henceforth be reckoned with. 



(5) Insensibly, again for it is all a matter 

 of degree we pass from the temporary dints 

 impressed upon the organism by the environ- 

 ment to those that last. There are many 

 cases in which the novel conditions provoke 

 a structural change from which there can be 

 no rebound, the limit of organic elasticity 

 having been passed. These lasting changes 

 are technically called " modifications " or 

 "acquired characters." A tree may be per- 

 manently blown out of shape; over-exertion 

 at high altitude may strain the heart beyond 

 repair; a man may be tanned for life by the 

 tropical sun. 



(6) Quite different from the last are cases 

 where some change in the environment of 



