Upon the basis of these structural, functional and mental differences, the qualitative and quantitative evolution of which in the race as in the individual is guided by the glands of internal secretion, Keith presents a very good case for the view that the white man is an example of relative excess of the pituitary, thyroid, adrenal and gonad endocrines.  “The sharp and 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” are the signs of pituitary dominance.  Keith is also of the opinion that “the sexual differentiation, the robust manifestations of the male characters, is more emphatic in the Caucasian than in either the Mongol or Negro racial types ... in certain negro types, especially in Nilotic tribes, with their long stork-like legs, we seem to have a manifestation of abeyance in the action of the interstitial glands.”  As for the adrenal superiority of the white man, “it is 150 years since John Hunter came to the conclusion ... that the original color of man’s skin was black, and all the knowledge that we have gathered since his supports the inference he drew.  From the fact that pigment begins to collect and thus darken the skin when the adrenal bodies become the seat of a destructive disease we infer that they have to do with the clearing away of pigment, and that we Europeans owe the fairness of our skins to some particular virtue resident in the adrenal bodies.”  Finally, as regards the thyroid, a comparison of the face of a cretin with that of the Negro or Mongol tells the story.  A certain variety of idiocy, Mongolian idiocy, in which the face simulates cretinism so closely as to deceive practised clinical observers, is characterized by a Chinese cast of the features and eyes, hence the name.  And in the Bushman of South Africa, the cretin’s face is even more startlingly recalled.

There is every reason then for believing that the white man possesses more of pituitary, adrenal, gonad, and thyroid internal secretions as compared with the yellow man or black man.  And since these endocrines control not only physique and physiognomy, anatomic and functional minutiae, but also mind and behaviour, we are justified in putting down the white man’s predominance on the planet to a greater all-around concentration in his blood of the omnipotent hormones.  While the Negro is relatively subadrenal, the Mongol is relatively subthyroid.  Their relative deficiency in internal secretions constitutes the essence of the White Man’s Burden.

MAN’S ATTITUDE TOWARD HIMSELF

A last, but by no means least, application we may consider of the developing knowledge of the internal secretions in relation to human evolution is its effect upon Man’s attitude toward himself and so toward his fellow men.  Whatever else he is, man is a land animal with ideas.  That makes him a thought-adventurer among materials.  In a word, he is the last word of mind working upon matter.  But persistently he has refused to recognize himself as matter and as subject to the laws, to the physics and chemistry of matter.