32 THE MENDEL JOURNAL 



diminution in the use made of the jaws and teeth in 

 feeding and fighting. If man is regarded as a single 

 species, then he affords a conspicuous instance against 

 the doctrine that specific characters are not adap- 

 tations, but it must be remembered that the con- 

 tention is not that no specific characters are adaptive, 

 but that in a vast number of cases several species are 

 distinguished and named which live in the same 

 district under the same conditions, and that where 

 they live in different habitats there is no evidence 

 that the characters correspond to differences in the 

 mode of life. On the other hand, there is no reason 

 why a single species should not become adapted to 

 some peculiar mode of life, but then it would be a 

 matter of opinion among systematists whether it 

 should not be placed in a separate genus. 



Before proceeding further with this part of the 

 subject, it is interesting to consider the origin and 

 nature of these adaptations. While others have been 

 disputing whether acquired characters are ever in- 

 herited and whether adaptations are due to the 

 inheritance of acquired characters, Dr. Archdall Reid 

 has made the brilliant discovery that such adaptations 

 as those which distinguish man from the anthropoid 

 apes are not inherited at all, but are acquired by every 

 individual in the course of his development. Inborn 

 or congenital characters, he says, are developed by 

 the stimulus of nutrition alone, acquired characters 

 are developed by the stimulus of use. Modifications 

 acquired as a result of use and disuse are clearly never 

 transmitted, because they never develop except in 



