November 13, 1919] 



NATURE 



303 



brother and a sister wjere of the same species, or that 

 the wrinkled, sallow-visaged eunuch with his beard- 

 less fate, his long, tapering limbs, his hesitating 

 carriage, his carping outioolv, and corpulent boi!y was 

 brother to the thicK-set, robust, pugilistic man with 

 the bearded face. 'Ihe discovery that the testicle and 

 ovary contain, scattered throughout their substance, a 

 small glandular element which has nothing to do with 

 their main tunction — tlie production of genital cells — 

 was made seventy years ago, but the evidence which 

 leads us to believe that tnis scattered element — the 

 interstitial gland — is directly concerned in the 

 mechanism of growth is of quite recent date. All 

 those changes which wo 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 tne matura- 

 tion of the body is both prolonged and altered. In 

 seeking for the mechanism which shapes mankind 

 into races we must take the interstitial gland into our 

 reckoning. 1 am of opinion that the sexual differen- 

 tiation — the robust manifestations of the male char- 

 acters — is more emphatic in the Caucasian than in 

 either the Mongol or Negro racial types. In both Mongol 

 and Negro, in their most representative form, we 

 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 inter- 

 stitial 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 

 small 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 darken- 

 ing or pigmentation of the patient's skin, besides 

 giving rise to other more severe changes and symp- 

 toms. Now it is 150 years since John Hunter came 

 to the conclusion, on the evidence then at his dis- 

 posal, that the original colour of man's skin was 

 black, and all the knowledge that we have gathered 

 since his 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 i 

 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 Sir E. A. Sharpey Schafer, of T. R. 1 

 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 boy or girl undergoes cer- 

 tain extraordinary growth changes. The sexual 

 organs become rapidlv 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. Prof. Glvnn 

 (Quart. Jonrn. of Med., vol. v., p. 157, iqiz) has 

 rerontlv collected such cases and systematised our 

 knowledge of these strange derangements of growth. 



NO. 261 1, VOL. TO4] 



There can be no doubt that the suprarenal bodies con- 

 stitute an important part of the mechanism which 

 regulates the development and growth of the human 

 body and helps in determining the racial characters of 

 mankind. We know that certain races come more 

 quickly to sexual maturity than others, and that races 

 vary in development of hair and of pigment, and it is 

 therefore reasonable to expect a satisfactory explana- 

 tion of these characters when we have come by a 

 more complete knowledge of the suprarenal 

 mechanism. 



During the last few years the totally unexpected 

 discovery has been sprung upon us that disease of 

 the minute pineal gland of the brain may give rise 

 to a train of symptoms very similar to those which 

 follow tumour formation of the cortex of the supra- 

 renal bodies. In some instances the sudden sexual 

 prematurity which occurs in childhood is apparently 

 the immediate result of a tumour-like affection of the 

 pineal gland. We have hitherto regarded the pineal 

 gland, little bigger than a wheat-grain and buried 

 deeply in the brain, as a mere useless vestige of a 

 median or parietal eye, derived from some distant 

 human ancestor in whom that eye w-as functional, 

 but on the clinical and experimental evidence now 

 rapidly accumulating we must assign to it a place in 

 the machinery which controls the growth of the bodv. 



We come now to deal with the thyroid gland, 

 which, from an anthropological point of view, must 

 be regarded as the most important of all the organs 

 or glands of internal secretion. Here, too, in con- 

 nection with the thyroid gland, which is situated in 

 the front of the neck, where it is so apt to become 

 (■nlarged and prominent in women, 1 must direct at- 

 tention to a generalisation which I jiurred over when 

 speaking of the pituitary and suprarenal glands. 

 Each of these glands throws into the circulating blood 

 two sets of substances — one set to act immediately in 

 tuning the parts of the body which are not under the 

 influence of the will to the work they have to do 

 when the body is at rest and when it is making an 

 effort ; another set of substances — which Prof. Gley 

 has named morphogenetic — has not an immediate but 

 a remote effect; they regulate the development and 

 co-ordinate the growth of the various parts of the 

 body. Now, so far as the immediate function of the 

 thyroid is concerned, our present knowledge points to 

 the gland as the manufactory of a substance which, 

 when circulating in the bodv, regulates the rate of 

 combustion of the tissues ; when we make a muscular 

 effort, or when our bodies are exposed to cold, or 

 when we become the subjects of infection, the thvroid 

 is called upon to assist in mobilising all available 

 tissue-fuel. If we consider onlv its immediate func- 

 tion it is clear that the thyroid is connected with the 

 selection and survival of human races. When, how- 

 ever, Tve consider its remote or morphogenetic effects 

 on growth, its importance as a factor in shaping the 

 characteristics of human races becomes even more 

 evident. In districts where the thyroid is liable to 

 that form of disease known as goitre it has been 

 known for manv a year that children who were 

 affected became cretins — dwarf idiots with a very 

 characteristic appearance of face and body.' Disease 

 of the thvroid stunts and alters the growth of the 

 bodv so that the subjects of this disorder might well 

 be classed as a separate species of humanity. If the 

 thyroid becomes diseased and defective after growth 

 of the bodv is completed, then certain changes, first 

 observed by Sir William Gull in 1873, are set up and 

 give rise to the disordered state of the bodv known as 

 myxoedema. "In th!<: state," says Sir Malcolm 



' Tht storv "f the dl'COverv of the action of the ihYroid gland is told by 

 Prof. G. M. Mlirrnv, Rri/. Mtd.Joum.. ii., p. 163, 1913. 



