THE FORMATION OF RACES. V.i'6 



are likewise in some manner connected. With the breeds of sheep 

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

 excretory pores are related.™ If we may judge from the analogy 

 of our domesticated animals, many modifications of structure in 

 man probably come under this principle of correlated develop- 

 ment. 



¥/e have now seen that the external characteristic differences 

 between the races of man cannot be accounted for in a satisfac- 

 tory manner by the direct action of the conditions of life, nor by 

 the effects of the continued use of parts, nor through the prin- 

 ciple of correlation. We are therefore led to inquire whether 

 slight individual differences, to which man is eminently liable, 

 may not have been preserved 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 err on this head, none of the 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 ex- 

 cepted from this remark. The great variability of all the ex- 

 ternal differences between the races of man, likewise indicates 

 that they cannot be of much importance; for if important, they 

 would long ago have been either fixed and preserved, or elimi- 

 nated. In this respect man resembles those forms, called by 

 naturalists protean or polymorphic, which have remained ex- 

 tremely variable, owing, as it seems, to such variations being of 

 an indifferent nature, and to their having thus escaped the ac- 

 tion of natural selection. 



We have thus far been baffled in all our attempts to account 

 for the differences between the races of man; but there remains 

 one important agency, namely Sexual Selection, which appears to 

 have acted powerfully on man, as on many other animals. I do 

 not intend to assert that sexual selection will account for all the 

 differences between the races. An unexplained residuum is left, 

 about which we can only say, in our ignorance, that as individu- 

 als are continually born with, for instance, heads a little rounder 

 or narrower, and with noses a little longer or shorter, such slight 

 differences might become fixed and uniform, if the unknown 

 agencies which induced them were to act in a more constant 

 manner, aided by long-continued intercrossing. Such variations 

 come under the provisional class, alluded to in our second chap- 

 hair, which Is hereditary. Now tliis hair is as coarse and harsh as 

 that of a horse's mane, whilst the hair of other colors is fine and soft. 

 <"> On the odor of the skin, Godron, 'Sur I'Espece,' torn. ii. p. 217. 

 On the pores in the sliin, Dr. Wilckens, 'Die Aufgaben der Land- 

 wirth. Zootechnik,' 1869, s. 7. 

 14 



