152 THE THEORY OF EVOLUTION 



The same experiments are interpreted in diamet- 

 rically opposite senses by different writers according 

 to their predisposition and general point of view. 

 At the present time, it is probable that a very con- 

 siderable majority of zoologists and botanists, espe- 

 cially in this country, are inclined to deny the 

 hereditary transmission of characters acquired in the 

 post-embryonic life of the parents, but the problem is 

 still far from definite solution. Important as this 

 problem is in any attempt to explain evolution and 

 the manner in which it has been effected, it has no 

 bearing upon the question which I have been en- 

 deavouring to answer in these lectures, as to the 

 probable truth of the evolutionary theory. That 

 theory is held quite as strongly by those who deny 

 as by those who affirm the transmission of acquired 

 characters. Whatever interpretation be put upon 

 the significance of the experiments, presently to be 

 mentioned, as to the problem of acquired characters, 

 they do, at all events, show that hereditarily trans- 

 missible modifications may be artificially produced 

 in both animals and plants. 



We are again, as in every one of the preceding 

 lectures, confronted by the difficulty of making an 

 instructive and convincing selection from a great and 

 ever growing mass of facts, but it is impossible to 

 present more than a few typical examples. Among 

 the older experiments may be mentioned those made 

 by Schmankewitsch upon the brine-shrimp. By 

 increasing the proportion of salt dissolved in the 



