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 
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