38 THE MENDEL JOURNAL 



as in other animals, that there are two categories of 

 characters, namely, the adaptive and the non- 

 adaptive. The latter are of the same kind as those 

 which are called mutations by modern biologists, 

 while the former, in my opinion, are directly due to 

 stimuli. Where the stimulus is functional, the 

 modification is such as to render organs and structures 

 more fitted for the functions ; but certain conditions 

 may produce a direct result which has no connection 

 with function, and which is, therefore, not in the 

 ordinary sense useful or adaptive ; for example, the 

 absence of light stimulus causes the absence of pig- 

 ment from the lower sides of flat fishes, but this 

 character is neither useful nor adaptive. The real 

 distinction between the two kinds of characters 

 according to my views is that those of one kind are 

 due to external stimulation, those of the other kind 

 are independent of external causes — the latter are 

 mutations, the former may be called modifications. 



Huxley's classification of the races of mankind is 

 a somewhat simple one. He divides them into two 

 primary divisions, resembling perhaps genera, namely, 

 the Ulotrichi with woolly hair, and the Leiotrichi 

 with straight hair. The Leiotrichi he subdivides into 

 four groups : the Australioid, the Mongoloid, the 

 Xanthochroi or fair whites, and the Melanochroi or 

 dark whites. The characters in which the races 

 differ are colour of skin, hair, and eyes, shape of 

 cranium, whether brachycephalic or dolichocephalic 

 character of hair, projection of jaws, shape of features, 

 especially nose and eye-apertures. The negro race 



