THE SUPPOSED TRANSMISSION OF MUTILATIONS. 435 



A very good instance is mentioned by Settegast, although per- 

 haps with another object in view. The various species of crows 

 possess stiff bristle-like feathers round the opening" of the nostrils 

 and the base of the beak : these are absent only in the rook. The 

 latter, however, possesses them when young, but soon after it has 

 left the nest they are lost and never reappear. The rook digs deep 

 into the earth in searching for food, and in this way the feathers 

 at the base of the beak are rubbed off and can never grow again 

 because of the constant digging. Nevertheless this peculiarity, 

 which has been acquired again and again from times immemorial, 

 has never led to the appearance of a newly hatched individual with 

 a bare face. 



Thus there is no reason for the assumption that such a result 

 would occur in the case of the mice even if the experiments had 

 been continued through hundreds or thousands of generations. 

 The supposition of the accumulative effect of mutilation is entirely 

 visionary, and cannot be supported except by the fact that accu- 

 mulative transformations of the germ-plasm occur; but of course 

 this fact does not imply that mutilations belong to those influences 

 which are capable of changing the germ-plasm. All the ascer- 

 tained facts point to the conclusion that they have not this 

 effect. The transmission is all the more improbable because of 

 the striking form of the mutilation in all cases which are relied 

 upon as evidence. The only objection which can be raised is to 

 suppose that the absence of the tail is less easily transmitted than 

 other mutilations, or that mice possess smaller hereditary powers 

 than other animals. But there is not the slightest evidence in 

 favour of either of these suggestions ; the supporters of the 

 Lamarckian principle have, on the contrary, always pointed to the 

 transmission of mutilated tails as one of their principal lines of 

 evidence. 



The opinion has often been expressed that such transmission need 

 not occur in every case, but may happen now and then under quite 

 exceptional conditions with which we are unacquainted: for this 

 reason it might be urged that all negative experiments and every 

 refutation of the ' proofs ' of the transmission of mutilations are not 

 conclusive. Only recently, a clever young zoologist said in reference 

 to Kant's statements upon the subject, that perhaps the most de- 

 cided opponent of the transmission of mutilations would not venture 



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