vii] HEREDITY 95 



morbid and the animals frequently nibble them aAvay. 

 A small percentage of the offspring of guinea-pigs 

 lacking toes from this cause also had toes missing. 

 But it has been pointed out that rodents in captivity 

 sometimes eat oif the toes or tails of their young, and 

 if the mother had acquired the habit of nibbling her 

 own toes, she might bite off those of her young 

 shortly after birth and give the appearance of the 

 inheritance of a mutilation [20, 29]. 



Quite recently Kammerer [19] in Vienna has made 

 some remarkable observations on salamanders and 

 a species of toad which seem to support the idea of 

 the inheritance of acquired characters. For example, 

 among other experiments, he finds that the animals 

 can be accustomed to lay their eggs in water instead 

 of on land, and the young become modified to suit 

 their new surroundings, and the modifications are 

 progressively increased in later generations. He 

 points out however that most of his results, like 

 those obtained by Tower (Chap, in), may have been 

 brought about by the action of environment on the 

 eggs at the time of maturation, but they differ from 

 Tower's in the regularity of their appearance and in 

 being adaptive. Further work in this direction will 

 be awaited with interest. 



On the whole, the hypothesis of the inheritance 

 of acquired characters must be regarded as 'not 

 proven,' and our increasing knowledge of the be- 



