6o6 POPULAR SCIENCE MONTHLY. 



ton, roughly classified, there were nine per cent of pure brunette 

 type among those of country birth and training, while among those 

 of urban birth and parentage the percentage of such brunette type 

 rose as high as fifteen. The arbitrary limit of twenty thousand in- 

 habitants was here adopted as distinguishing city from suburban 

 populations. Dark hair was noticeably more frequent in the last 

 named group. 



It is not improbable that there is in brunetteness, in the dark 

 hair and eye, some indication of vital superiority. If this were so, 

 it would serve as a partial explanation for the social phenomenon 

 which we have been at so much pains to describe. If in the same 

 community there were a slight vital advantage in brunetteness, we 

 should expect to find that type slowly aggregating in the cities; 

 for it requires energy and courage, physical as well as mental, not 

 only to break the ties of home and migrate, but also to maintain 

 one's self afterward under the stress of urban life. Selection thus 

 would be doubly operative. It would determine the character both 

 of the urban immigrants and, to coin a phrase, of the urban per- 

 sistents as well. The idea is worth developing a bit. 



Eminent authority stands sponsor for the theorem that pig- 

 mentation in the lower animals is an important factor in the great 

 struggle for survival.* One proof of this is that albinos in all 

 species are apt to be defective in keenness of sense, thereby being 

 placed at a great disadvantage in the competition for existence 

 with their fellows. Pigmentation, especially in the organs of 

 sense, seems to be essential to their full development. As a result, 

 with the coincident disadvantage due to their conspicuous color, 

 such albinos are ruthlessly weeded out by the processes of natural 

 selection; their non-existence in a state of Nature is noticeable. 

 Darwin and others cite numerous examples of the defective senses 

 of such non-pigmented animals. Thus, in Virginia, the white pigs 

 of the colonists perished miserably by partaking of certain poison- 

 ous roots which the dark-colored hogs avoided by reason of keener 

 sense discrimination. In Italy, the same exemption of black sheep 

 from accidental poisoning, to which their white companions were 

 subject, has been noted. Animals so far removed from one another 

 as the horse and the rhinoceros are said to suffer from a defective 

 sense of smell when they are of the albino type. It is a fact of 

 common observation that white cats with blue eyes are quite often 

 deaf. 



Other examples might be cited of similar import. They all 

 tend to justify Alfred Russel Wallace's conclusion that pigmenta- 



* Dr. William Ogle, in Medico-Chirurgical Transactions, liii, 1870, pp. 263 et seq. 



