46 PROBLEMS OF EVOLUTION 



Supposed There ought to be no need to write at length on this matter; 

 instances j t ^ as b een d ea it with fully and clearly by Weismann. 1 How- 

 heritance ever, the wrangling on the subject still continues, and much of 



lt ' ls due to m i sa PP renens i n - At tne outset, it is highly im- 

 teristics portant to explain what is meant by the non-inheritance of 

 acquired characteristics, since there is often a failure to com- 

 prehend clearly the question at issue. Suppose that a pianist 

 develops great strength and dexterity of finger, and suppose 

 that his son becomes a pianist and also develops his fingers in 

 the same way. The father, probably, was born with hands well 

 adapted to piano-playing. The son may, very probably, have 

 inherited his power of muscle and bone. The point at issue 

 between Lamarckians and their opponents is whether the son 

 has greater innate capacity because his father developed what 

 he had as a natural gift ; whether, in fact, the father through 

 long practice at his art transmitted to his son increased power 

 beyond what otherwise would have been inherited. It is almost 

 impossible to imagine a subject on which it is harder to find 

 positive evidence than on this. The Lamarckians have presented 

 one case after another, and Weismann, as far as I can judge, has 

 disposed of them each in turn. He has been able to show that 

 the predisposition, that made the acquisition possible, has been 

 undoubtedly transmitted, while, as to the acquired increment, 

 the facts do not warrant us in believing in its transmission. 

 The There is one argument of which I do not think enough has 

 Pini and been made. The scientific breeder of cattle or any of our 

 practice of domestic animals stands to his animals in the place of nature. 

 rs He determines what characteristics shall mark the race as nature 

 decides in the case of wild animals. Now, breeders have never 

 trusted much to Lamarckian methods, and, as far as I know, 

 tend to become less and less Lamarckian. 2 No breeder of hom- 

 ing pigeons holds that young birds are any the better if their 

 parents have been highly trained before they bring them into 



1 See his first vol. of Essays : Essay II. on Heredity and IV. on the continuity of the 

 germ- plasm, 



2 It must be owned, however, that American breeders like American biologists 

 seem to have Lamarckian tendencies. See Cope's Primary factors of Evolution. 



