374 EVOLUTION OF PHYSICAL CHAEACTEES 



of these characters when we have come by a more or less complete 

 knowledge of the supra-renal mechanism.' ^ The thyroid acts 

 directly upon the skin and the hair and also upon the skeleton. 

 ' This is particularly the case as regards the base of the skull 

 and the nose, the arrest of growth falls mainly upon the basal parts 

 of the skull with the result that the root of the nose appears to 

 be flattened and drawn backwards between the eyes, the upper 

 forehead appears projecting or bulging, the face appears flattened, 

 and the bony scaffolding of the nose particularly when compared 

 with the prominence of the jaw is greatly reduced. Now these 

 facial features which I have enumerated give the Mongolian 

 face its characteristic aspect, and, to a lesser degree, they are 

 also to be traced in the features of the negro. Indeed, in one 

 aberrant branch of the negro race — the Bushman of South Africa — 

 the thyroid facies is even more emphatically brought out than 

 in the most typical Mongol, You will observe that, in my opinion, 

 the thyroid — or a reduction or alteration in the activity of the 

 thyroid — has been a factor in determining some of the racial 

 characteristics of the Mongol and Negro races. I know of a telhng 

 piece of evidence which supports this thesis. Some years ago 

 there died in the East End of London a Chinese giant — the subject 

 one must suppose of an excessive action of the pituitary glands — 

 the gland which I regard as playing a predominant part in shaping 

 the face and bodily form of the European. The skeleton of this 

 giant w^as prepared and placed in the museum of the London 

 Hospital Medical College by Col. T. H. Openshaw, and any one 

 inspecting that skeleton can see that, although certain Chinese 

 features are still recognizable, the nasal region and the supra- 

 orbital ridges of the face have assumed the more prominent 

 European type.' - 



4. If we turn now and look at the conditions of life among 

 primitive races, we find that natural selection and differential 

 fertility tend to work towards the preservation of existing types 

 rather than towards further evolution. The Australians may 

 have existed in their present home for many thousands of years 

 without undergoing any considerable change of type, and we have 

 every reason to suppose that, if they had been left untouched 

 by white or other races, the racial type would have remained 

 substantially the same for thousands of years to come. The same 



1 Keith, Nature, vol. civ, p. 303. ' Ibid., p. 404. 



