sQS The Descent of Man. Pakt l. 



omitted "by it, are likewise in some maimer connected. With the 

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

 number of the excretory pores are related. 69 If we may judge 

 from the analogy of our domesticated animals, many modifica- 

 tions of structure in man probably come under this principle of 

 correlated development. 



We 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 

 principle of correlation. We are therefore led to inquire 

 whether slight individual differences, to which man is emi- 

 nently 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 excepted from this remark. The great 

 variability of all the external 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 eliminated. In this respect man resembles those 

 forms, called by naturalists protean or polymorphic, which have 

 remained extremely variable, owing, as it seems, to such varia- 

 tions being of an indifferent nature, and to their having thus 

 escaped the action 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 indivi- 

 duals 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 



the Marxians, about one in ten or fine and soft. 



twelve of the members, of all ages 69 On the odour of the skin, 



and both sexes, have bright silvery Godron, ' Sur l'Espece,' torn. ii. p. 



grey hair, which is hereditary. 217. On the pores in the skin. 



Now this hair is as coarse and Dr. Wilckens, ' Die Aufgaben der 



harsh as that of a horse's mane, Landwirth. Zootechnik,' 1869, s. 7. 

 whilst the hair cf other coloux - ? is 



