206 HEREDITARY CHARACTERS 



sexual glands be completely removed in the young male, 

 the secondary sexual characters do not appear. It would 

 seem, therefore, that when the cells forming the male sexual 

 gland are present, the male secondary sexual characters 

 appear whether the individual be male or female. There 

 are other facts which also suggest that the potentiality for 

 producing these characters is present in both sexes. For 

 instance, old hens (e.g. pheasants), when they have passed 

 the period of laying eggs, not infrequently develop the 

 plumage of the male bird. The same kind of thing is 

 frequently seen in the human race, where old women grow 

 hair upon their faces. Now this seems to be quite different 

 to what happens in the case of the Mendelian characters. 

 There is no evidence in many of the Mendelian experiments 

 that sex has anything to do with their mode of transmission, 

 In those where segregation appears to be most complete, 

 the individuals are self-fertilised, so in these cases it is 

 obvious that sex is not alternative. The dividing of char- 

 acters into " individual " and " racial " makes it possible to 

 explain why some characters are transmitted in an alter- 

 native manner, while others blend. Apart from this there 

 seems to be no explanation of the Mendelian phenomena. 

 Archdall Reid says that Mendelian characters may be fairly 

 described as secondary sexual characters. 1 By this it must 

 be supposed he means that secondary sexual characters 

 are similar in nature to those which have been found to 

 give more or less complete Mendelian results. But when 

 we come to look into the matter carefully, we find that 

 characters that give Mendelian results in the case of one 

 race, do not do so in another race. Colour has been used 

 in the Mendelian experiments as much as any other char- 

 acter, yet in man colour blends when crossed. Many of the 

 examples of blending previously quoted 2 might just as fairly 

 be described as secondary sexual characters, but there is 

 not the slightest evidence to show that they are, and much 

 which suggests that they are not. Many such characters, 



1 See p. 202. 2 See pp. 118, 186. 



