CHAPTER FIVE 



THE QUESTION OF THE INHERITANCE OF ACQUIRED 

 CHARACTERS 



The great service of Weismann, which is not yet 

 appreciated highly enough, is that he brought forward 

 this matter of the inheritance of acquired characters, and 

 questioned its existence, which previously had been not 

 only tacitly admitted by most biologists, but regarded as 

 not needing proof. And we must recognize the fact that 

 the great and justifiable desire to find for this inheritance 

 some proof which should be irrefutable and not open to 

 any objections has remained so far unfulfilled. 



It is not proposed here to make a long list of all the 

 facts which have been brought forward as proofs of the 

 Lamarckian principle, but it will be worth while to 

 examine a few in order to show clearly that Weismann and 

 his school are not really far wrong in denying to most of 

 these facts any right to be considered conclusive proof. 



We shall leave aside the question as to whether calves 

 have really been born without horns, as alleged, in con- 

 sequence of the breaking off before their conception of 

 the horns of one or other parent; or whether tailless 

 calves were produced by a bull whose tail had been 

 squeezed off at the root by the violent closing of the stable 

 door. It is clear that all these cases and many others like 

 them, which have been reported in dogs, cats, rats, and 



