EVOLUTION OF PHYSICAL CHARACTEES 373 



of one or more of these glands. It must be supposed that one 

 or more of the results of the developments of a gland are of 

 direct value in facing the peculiar conditions, whether climatic 

 or otherwise, to which the race is subject, and that the other 

 consequences of the development of the gland are in any case 

 not prejudicial. These other consequences may possibly take the 

 form of noticeable peculiarities of colour or of bodily structure 

 which thus turn out in themselves not to be of survival value 

 but merely to be, so to speak, accidental peculiarities. 



Some quotations from Professor Keith's exposition of this 

 suggestion may make the matter more clear. ' When we compare ', 

 he says, ' the three chief racial types of humanity — the Negro, 

 the Mongol, and the Caucasian or European — we can recognize 

 in the last-named a greater predominance of the pituitary than 

 in the other two. The sharp pronounced nasalization of the face, 

 the tendency to strong eyebrow ridges, the prominent chin, the 

 tendency to bulk of body and height of stature in the majority 

 of Europeans, is best explained, so far as the present state of our 

 knowledge goes, in terms of pituitary functions.' ^ After remark- 

 ing that the interstitial glands are largely the cause of secondary 

 sexual differences he goes on to say : ' I am of opinion that the 

 sexual differentiation — the robust manifestation of the male 

 characters — is more emphatic in the Caucasian than in either the 

 Mongol or Negroid racial types. In both Mongol and Negro, in 

 their most representative form, we find a beardless face and an 

 almost hairless body, and in certain negro types, especially in 

 Nilotic tribes, with their long, stork-like legs, we seem to have 

 a manifestation of the abeyance in the action of the interstitial 

 glands. At the close of sexual life we often see the features of 

 a woman assume a coarser and more masculine appearance.' ^ 

 Later he remarks that the evidence points to the original human 

 colouring as black. Now, the supra-renal bodies cause a clearing 

 away of pigment and ' there can be no doubt that the supra- 

 renal bodies constitute an important part of the mechanism which 

 regulates the development and growth of the human body and 

 helps in determining the racial characters of mankind. We know 

 that certain races come more quickly to sexual maturity than 

 others, and that races vary in development of hair and of pigment, 

 and it is therefore reasonable to expect a satisfactory explanation 



' Keith, Nature, vol. civ, p. 302. ^ Ibid., p. 303. 



