276 TRANSACTIONS OF SECTION H. 



cannot produce that complex of features whicii marks off one racial type from 

 another. Nature has at her command some secret mechanism by which she 

 works out her new patterns in the bodies of man and least — a mechanism of 

 which we were almost ignorant in Darwin's day, but which we are now 

 begimiing to perceive and dimly understand. It is the bearing of this creative 

 or morphogenetic mechanism on the evolution of the modem races of mankind 

 which I propose to make the subject of my address. 



Hid away in various parts of the human frame is a series of more or 

 less obscui'e bodies or glands, five in number, which, in recent times, we have 

 come to recognise as parts of the machinery which regulate the growth of 

 the body. They form merely a fraction of the body — not more than 1/ 180th 

 part of it ; a man might pack the entire series in his watch-pocket. The modern 

 medical student is familiar with each one of them — the pituitary body, about 

 the size of a ripe cherry, attached to the base of the brain and cradled in the 

 floor of the skull; the pineal gland, also situated in the brain, and in point of 

 size but little larger than a wheat-grain ; the thyroid in the neck, set astride 

 the windpipe, forms a more bulky mass ; the two suprarenal bodies situated in 

 the belly, capping the kidneys, and the interstitial glands embedded within 

 the substance of the testicle and ovary, complete the list. The modern physician 

 is also familiar with the fact that the growth of the body may be retarded, 

 accelerated, or completely altered if one or more of these glands becomes the 

 seat of injury or of a functional disorder. It is thirty-three years now since first 

 one woman and then another came to Dr. Pierre Marie in Paris seeking relief 

 from a persistent headache, and mentioning incidentally that their faces, bodies, 

 hands, and feet had altered so much in recent years that their best-known 

 friends failed to recognise them. That incident marked the commencement of 

 our knowledge of the pituitary gland as an intrinsic part of the machinery 

 which regulates the shaping of our bodies and features. Dr. Marie named the 

 condition acromegaly. Since then hundreds of men and women showing 

 symptoms s.'milar to those cf Dr. Marie's patients have been seen and diagnosed, 

 and in every instance where the acromegalic changes were typical and marked 

 there has been found a definite enlargement or tumour of the pituitary body. 

 The practised eye recognises the full-blown condition of acromegaly at a glance, 

 so characteristic are the features of the sufferers. Nay, as we walk along the 

 streets vre can note slight degrees of it — degrees which fall far short of the 

 border-line of disease ; we note that it may give characteristic traits to a whole 

 family — a family marked by what may be named an acromegalic taint. The 

 pituitary gland is also concerned ir another disturbance of growth — giantism. 

 In every case where a young lad has shot up, during his late ' teens,' into a 

 lanky man of seven feet or more — ^has become a giant — it has been found that 

 his pituitary gland was the site of a disordered enlargement. The pituitary is 

 part of the mechanism which regulates our stature, and stature is a racial 

 characteristic. The giant is usually acromegalic as well as tall, but the two 

 conditions need not be combined ; a young lad may undergo the bodily changes 

 which characterise acromegaly and yet not become abnormally tall, or he may 

 become — although this is rarely the case — a giant in stature and yet may not 

 assume acromegalic features. There is a third condition of disordered growth 

 in which the pituitary is concerned — one in which the length of the limbs 

 is disproportionably increased — in which the sexual system and all the secondary 

 sexual characters of body and mind either fail to develop or disappear — where 

 fat tends to be deposited on the body, particularlj' over the buttocks and 

 thighs — where, in brief, a eunuchoid condition of body develops. In all of these 

 three conditions we seem to be dealing with a disordered and exaggerated action 

 of the pituitary gland ; there must be conditions of an opposite kind where the 

 functions of the pituitary are disordered and reduced. A number of cases of 

 dwarfism have been recorded where boys or gii'ls retained their boyhood or 

 girlhood throughout life, apparently because their pituitaiy gland had been 

 invaded and partly destroyed by tumo.irs. We shall see that dwarfism may 

 result also from a failure nf the thvroid gland. On the evidence at our dis- 

 posal, evidence which is being rapidly augmented, we are justified in regarding 

 the pituitary gland as one of the principal pinions in the machinery which 

 regulates the growth of the human body and is directly concerned in deter- 

 mining statiire, cast of features, texture of skin, and character of hair — all of 



