Chap. VII.] THE KACES OF MAN. 239 



The color of the skin and the odor emitted by it are like- 

 wise in some manner connected. With the breeds of 

 sheej) the number of hairs within a given space and the 

 number of the excretory pores stand in some relation to 

 each other." If we may judge from the analogy of our 

 domesticated animals, many modifications of structure in 

 man probably come under this principle of correlated 

 growth. 



We have now seen that the characteristic differences 

 between the races of man cannot be accounted for in a 

 satisfactory manner by the direct action of the conditions 

 of life, nor by the effects of the continued use of parts, nor 

 through the principle of correlation. We are therefore 

 led to inquire whether slight individual differences, to 

 which man is eminently liable, may not have been pre- 

 served and augmented during a long series of generations 

 through natural selection. But here we are at once met 

 by the objection that beneficial variations alone can be 

 thus preserved ; and as far as we are enabled to judge 

 (although always liable to error on this head) not one of 

 the external differences between the races of man are of 

 any direct or special service to him. The intellectual and 

 moral or social faculties must of course be excepted from 

 this remark ; but differences in these faculties can have 

 had little or no influence on external characters. The 

 variability of all the characteristic differences between 

 the races, before referred to, likewise indicates that these 

 differences cannot be of much importance ; for, had they 



of the members of all ages and both sexes have bright silvery gray hair, 

 which is hereditary. Now this hair is as coarse and harsh as that of a 

 horse's mane, while the hair of other colors is fine and soft. 



54 On the odor of the skin, Godron, 'Sur l'Espece,' torn. ii. p. 217. 

 On the pores in the skin, Dr. Wilckens, ' Die Aufgaben der landwirth. 

 Zootechnik,' 1869, s. 1. 



