INHERITANCE OF ACQUIRED CHARACTERS 179 



" In the first place, the assertion that congenital stump-tails 

 in dogs and cats depended on inherited mutilation proved to be 

 unfounded. In none of the cases of stump-tails brought forward 

 could it even be proved that the tail of the relevant parent had 

 been torn or cut off, much less that the occurrence, in parents or 

 grandparents, of short tails from internal causes was excluded. 

 At the same time anatomical investigation of such stump-tails as 

 occur in cats in the Isle of Man, and in many Japanese cats, and 

 are frequently found in the most diverse breeds of dogs, showed 

 that these had, in their structure, nothing in common with the 

 remains of a tail that had been cut off, but were spontaneous 

 degenerations of the whole tail, and are thus deformed tails, not 

 shortened ones (Bonnet). 



" Experiments on mice also showed that the cutting off of the 

 tail, even when performed on both parents, does not bring about 

 the slightest diminution in the length of tail in the descendants. 

 I have myself instituted experiments of this kind, and carried 

 them out through twenty-two successive generations, without any 

 positive result. Corroborative results of these experiments on 

 mice have been communicated by Ritzema Bos and, indepen- 

 dently, by Rosenthal, and a corresponding series of experiments 

 on rats, which these two investigators carried out, yielded the 

 same negative results. 



" When we remember that all the cases which have been 

 brought forward in support of an inheritance of mutilations 

 refer to a single injury to one parent, while, in the experiments, 

 the same mutilation was inflicted on both parents through 

 numerous generations, we must regard these experiments as a 

 proof that all earlier statements were based either on a fallacy 

 or on fortuitous coincidence. This conclusion is confirmed by 

 all that we know otherwise of the effects of oft-repeated mutila- 

 tions, as for instance the well-known mutilations and distortions 

 which many peoples have practised for long, sometimes incon- 

 ceivably long, ages on their children, especially circumcision, the 

 breaking of the incisors, the boring of holes in lip, ear, or nose, 

 and so forth. No child of any of these races has ever been 

 brought into the world with one of these marks ; they have to be 

 re-impressed on every generation." * 



It cannot be seriously questioned that in the majority of cases 

 mutilations are not visibly inherited, but the fact that no one has 

 as yet succeeded in producing experimentally an inheritable 

 mutilation does not prove that such never occur accidentally. 



Weismann's arguments can hardly be regarded as conclusive 

 against such strong evidence as that afforded by Professor Hilgard's 



1 \Vei.smann, -'Tlie Evolution Theorj^ v (London, l'J04), Vol. II., pp. <!5-G. 



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