NON-TRANSMISSION OF MUTILATIONS 67 



of their antagonism, to deal briefly with the Lamarckian theory, 

 and to examine some objections against it, which, indeed, seem 

 to render it valueless. 



It has been often alleged that results of mutilation are trans- 

 missible. At the congress of German scientists held at Wies- 

 baden in 1887 dogs and cats were exhibited whose tails were 

 abnormally short, and it was alleged that this shortness had 

 been inherited from the parents, whose tails had been cut off. 

 It was Hkewise alleged that mutilations, such as scars, or slight 

 deformations of the lobe of the ear, were also transmissible ^ 

 But a belief in the transmission of mutilations has now been 

 abandoned, even by most of the apologists for Lamarckism ; 

 for, in the first place, the allegations respecting the transmission 

 of mutilated tails, scars, and the like, turn out to be wholly 

 worthless. When they were submitted to a rigorous examina- 

 tion no weU-authenticated evidence was forthcoming, and no 

 guarantee could be given even as to the accuracy of the essential 

 fact — ^namely, that one or other of the parents of the mutilated 

 animals had been in reality mutilated. In the second place, 

 experiments made by Weismann on no less than twenty-two 

 successive generations of mice, in which the tail of both parents 

 was in every case cut off, yielded an entirely negative result ; 

 not one of the 1,592 mice born in successive generations from 

 mutilated parents bore a trace of this mutilation which had been 

 inflicted on both parents. This experiment of Weismann's may 

 be fairly regarded as decisive as far as the]^transmission of somatic 

 mutilations is concerned. In the third place, it has been demon- 

 strated, notably by Bonnet, that those cases in which dogs and 

 cats are born with abnormally short tails are not due to the 

 inheritance of similar mutilations inflicted on one or other of 

 the parents, but that the nature of these inborn mutilations is 

 entirely difEerent from that of acquired mutilations. As a matter 

 of fact, such inborn mutilations are the result of spontaneous 

 regressive variation of the tail due to natural internal causes, 



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