PRESIDENTIAL ADDRESS. 277 



them marks of race. When we compare the three chief racial types of humanity— 

 the Negro, the Mongol, and the Caucasian or European — we can recognise in the 

 last named a greater predomimmce of the pituitary tlian in the other two. 

 The sharp and pronounced nasalisation of the face, the tendency to strong eye- 

 brow ridgea, the prominent chin, the tendency to bulk of body and height of 

 etature in the majority of Europeans, is best explained, so far as the present 

 state of our knowledge goes, in terms of pituitary function. 



There is no question that our interest in the mechanism of growth has been 

 quickened in recent years by observations and discoveries made by physicians 

 on men and women who suffered from pituitary disorders, but that a small 

 part of the body could influence and regulate the growth and characterisation 

 of the whole was known in ancient times. For many centuries it has been 

 common knowledge that the removal of the genital glands alters tlie external 

 form and niternal nature of man and beast. The sooner the operation is per- 

 formed after birth the more certain are its effects. Were a naturalist from a 

 unisexual world to visit this earth of ours it would be difficult to convince him 

 that a brother and a sister were of the same species, or that the wrinlcled, 

 sallow-visaged eunuch with his beardless face, his long tapering limbs, his 

 hesitating carriage, his carping outlook and corpulent body, was brother to the 

 thick-set, robust, pugilistic man with the bearded face. The discovery that 

 the testicle and ovary contain, scattered throughout their substance, a small 

 glandular element which has nothing to do with their main function— the pro- 

 duction of genital cells — ^was made seventy years ago, but the evidence which 

 leads us to believe that this scattered element — the interstitial gland — is directly 

 concerned in the mechanism of growth is of quite recent date. All those changes 

 which we may observe in the girl or boy at puberty— the phase of growth which 

 brings into full prominence their racial characteristics— depend on the action 

 of the interstitial glands. If they are removed or remain in abeyance the 

 maturation of the body is both prolonged and altered. In seeldng for tlie 

 mechanism which shapes mankind into races we must take the interstitial gland 

 into our reckoning. I am of 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 tjrpes. In both ^Mongol and Negro, in 

 their most representative form, w© find a beardless face and 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 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. 



Associated with the interstitial glands, at least in point of development, 

 are the suprarenal bodies or glands. Our knowledge that these two comparatively 

 email structures, no larger than the segments into which a moderately sized 

 orange can be separated, are connected with pigmentation of the skin dates 

 back to 1894, when Dr. Thomas Addison, a physician to Guy's Hospital, London, 

 observed that gradual destruction of these bodies by disease led to a darkening 

 or pigmentation of the patient's skin, besidas giving rise to other more severe 

 changes and symptoms. Now it is 150 years since John Hunter came to the 

 conclusion, on the evidence then at his disposal, that the original colour of 

 man's skin was black, and all the knowledge that we have gathered since hie 

 time supports the inference he drew. From the fact that pigment begins to 

 collect in and thus darken the skin when the suprarenal 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 suprarenal bodies. That their function is 

 complex and multiple, the researches of Sharpey-Schafer, of T. R. Elliott, and 

 of W. B. Cannon have made very evident. Fifteen years ago Bulloch and 

 Sequeira established the fact that when a suprarenal body becomes the site of 

 a peculiar form of malignant overgrowth in childhood, the body of the bov or 

 girl undergoes certain extraordinary growth changes. "The sexual organs become 

 rapidly mature, and through the framework of childhood burst all the features 

 of sexual maturity — the full chest, muscularity of limbs, bass voice, bearded 

 face and hairy body — a miniature Hercules — a miracle of transformation in 

 body and brain. Corresponding changes occur in young girls — almost infants 

 in years — with a tendency to assume features which characterise the male 

 1919. 7 



