226 THE PHILOSOPHY OF BIOLOGY 



work actually carried out. Most of the experiments 

 deal with the consideration of traumatic lesions or 

 mutilations, and it seems to be proved that such 

 defects are not transmitted, or at least are very 

 rarely transmitted. The tails of kittens have been 

 cut off ; the ears of terrier-dogs have been lopped ; 

 and the feet and waists of Chinese and European 

 ladies have been compressed, and all throughout 

 very numerous generations, yet these defects are not 

 transmitted from parent to offspring. This kind of 

 evidence forms the bulk of that which orthodox 

 zoological opinion has adduced in favour of the belief 

 in the non-inheritabiiity of acquired characters, but 

 does it all really matter ? What might be transmitted 

 is a useful, purposeful modification of morphology, 

 or functioning, or behaviour, induced by the environ- 

 ment throughout a number of generations — an adapta- 

 tion rather than a harmful lesion. There is little 

 conclusive evidence that such adaptations are inherited, 

 though anyone who carefully studies the evidence in 

 existence will not be likely to say that they are 

 certainly not transmitted. Does, for instance, the 

 blacksmith transmit his muscular shoulders and arms 

 to his sons, or the pianiste her supple wrists and 

 fingers to her daughters ? There are no observations 

 and experiments in the literature worthy of the 

 importance attaching to the question at issue. 



It should be noted also that the germ-plasm is 

 certainly not the immutable substance that the hypo- 

 thesis originally postulated. Changes in the outer 

 physical environment may certainly affect it ; thus 

 the larvae bred from animals which live in abnormal 

 physical conditions (temperature, moisture, etc.) may 

 differ morphologically from the larvae bred from animals 

 belonging to the same species but living in a normal 



