212 HEREDITY AND EUGENICS 



Enlargement of the pituitary is also frequently 

 associated with gigantism. Dwarfism may result 

 from an invasion of the pituitary by tumours, and 

 also from a failure of functioning on the part of the 

 thyroid. If such conditions are induced by deranged 

 functioning of these glands, it is reasonable to suppose 

 that corresponding racial (inherited) differences would 

 arise from germinal changes, w^hose effect is to alter 

 the cjuantity (or quality) of these secretions. The 

 Caucasian,* according to Keith, shows a greater pre- 

 dominance of the pituitary than the Negro or Mongol, 

 as indicated by the pronounced nasalisation of the 

 face, the tendency to strong eyebrow ridges, prom- 

 inent chin, and the tendenc}^ to greater stature 

 and bulk of body. It is also suggested that the 

 beardless face and almost hairless body of the repre- 

 sentative Negro and Mongol types is due to a lesser 

 activity of the interstitial glands, the long stork-like 

 legs of Nilotic and other tribes resulting from a greater 

 abeyance of the same glands. 



In the same way, differences in the pigmentation 

 of the skin, which characterise the various races of 

 mankind, may be reasonably assumed to be due to 

 inherited differences in the activities of the suprarenal 

 bodies, since it is known that Addison's disease, in 

 which, among other symptoms, there is a darkening 

 of the skin through pigmentation, is the result of a 

 pathological condition of the adrenal cortex. Thus, 

 the great colour varieties of mankind are probably 

 determined in part by differences in the activity of 

 the adrenal bodies ; but it is probable that other 



* Of course, anthropologists now recognise that there is no 

 Caucasian race, but that modern European populations are a 

 mixture in various proportions of three distinct races: (i) Nordic 

 tall, blue-eyed, and long-headed (dolichocephalic); (2) Alpine, 

 short and stocky, brown-eyed and broad-headed (brachycephalic) ; 

 (3) Mediterranean, small and slender, brown-eyed and long- 

 headed. 



