November 13, 1919] 



NATURE 



305 



munication between its inhabitants. We believed that : 

 it was only by nerve-fibres that intercommunication 

 was established in the animal body. Bayliss and 

 Starling showed that there was a postal system. 

 Missives posted in the general circulation were duly 

 delivered at their destinations. The manner in which 

 they reached the right address is of particular im- 

 portance for us ; we must suppose that the missive 

 or hormone circulating in the blood and the recipient 

 for which they are intended have a special attraction 

 or affinity for each other — one due to their physical 

 constitution — and hence they, and only they, come 

 together as the blood circulates round the body. 

 Secretin is a hormone which effects its errand 

 rapidly and immediately, whereas the growth or 

 morphogenetic hormones, thrown into the circulation 

 by the pituitary, pineal, thyroid, suprarenal, and 

 genital glands, act slowly and remotely. But both 

 are alike in this ; the result depends not only on 

 the nature of the hormone or missive, but also on 

 the state of the local recipient. The local recipient 

 may be specially greedy, as it were, and seize more 

 than a fair share of the manna in circulation, or it 

 mav have "sticky fingers" and seize what is not 

 really intended for local consumption. We can see 

 that local growth — the development of a particular 

 trait or feature — is dependent not only on the hor- 

 mones supplied to that part, but also on the condi- 

 tion of the receptive mechanism of the part. Hence 

 we can understand a local derangement of growth — 

 an acromegaly or giantism confined to a finger or to 

 the eyebrow ridges, to the nose, to one side of the 

 face, and such local manifestations are not uncom- 

 mon. It is by a variation in the sensitiveness of the 

 local recipient that we have an explanation of the 

 endless variety to be found in the relative develop- 

 ment of racial and individual features. 



Some ten years after Starling had formulated the 

 theory of hormones. Prof. W. B. Cannon, of Harvard , 

 University, piercing together the results of researches 

 by Dr. T. R. Elliott and by himself on the action of 

 the suprarenal glands, brought to light a very 

 wonderful hormone mechanism — one which helps us 

 in interpreting the action of growth-regulating hor- 

 mones. When we are about to make a severe bodilv 

 effort it is necessary to flood our muscles with blood, 

 so that thev may have at their disposal the materials 

 necessary for work — oxygen and blood-sugar, the fuel 

 of muscular engines. At the beginning of a muscular 

 effort the suprarenal glands are set going by mes- 

 sages passing to them from the central nervous 

 system ; they throw a hormone — adrenalin — into the 

 circulating blood, which has a double effect ; adrenalin 

 acts on the flood-gates of the circulation, so that the 

 major supply of blood passes to the muscles, hi the 

 same time it so acts on the liver that the blood cir- 

 culating through that great organ becomes laden with 

 blood-sugar. We here obtain a glimpse of the neat 

 and effective manner in which hormones are utilised 

 in the economy of the living body. From that 

 glimpse we seem to obtain a clue to that remarkable 

 disorder of growth in the human body known as : 

 acromegaly. It is a pathological manifestation of an 

 adaptational mechanism with which we are all 

 familiar. Nothing is better known to us than that . 

 our bodies respond to the burden they are made to I 

 bear. Our muscles increase in size and strength the ! 

 more we use them ; increase in the size of our 

 muscles would be useless unless our bones also were j 

 strengthened to a corresponding degree. K greater 

 blood supply is required to feed them, and hence the 

 power of the heart has to be augmented ; more 

 oxygen is needed for their consumption, and hence 

 the lung capacity has to be increased ; more fuel is ! 

 required — hence the whole digestive and assimilative 

 NO. 261I, VOL. 104] 



systems have, to undergo a hypertrophy, including the 

 apparatus of mastication. Such a power of co- 

 ordinated response on the part of all the organs 

 of the body to meet the needs of athletic training pre- 

 supposes a co-ordinating mechanism. We have 

 always regarded such a power of response as an 

 inherent property of the living body, but in the light 

 of our growing knowledge it is clear that we are 

 here dealing with an hormonic mechanism, one in 

 which the pituitary gland is primarily concerned. 

 When we study the structural changes which take 

 place in the first phase of acromegaly (see Keith, 

 Lancet, ii., p. 993, igii; i., p. 305, 1913), we find 

 that not only are the bones enlarged and overgrown 

 in a peculiar way, but also the muscles, the heart, 

 the lungs, the organs of digestion, particularly the 

 jaws ; hence the marked changes in the face, for 

 the form of the face is determined by the develop- 

 ment of the upper and lower jaws. The rational 

 interpretation of acromegfily is that it is a patho- 

 logical disorder of the mechanism of adaptational 

 response; in the healthy body the pituitary is throw- 

 ing into the circulation just a sufficiency of a growth- 

 regulating substance to sensitise muscles, bones, and 

 other structures to give a normal response to the 

 burden thrown on the body. But in acromegaly the 

 body is so flooded with this substance that its tissues 

 become hypersensitive and respond by overgrowth to 

 efforts and movements of the slightest degree. It is 

 not too much to expect, when we see how the body 

 and features become transformed at the onset of 

 acromegaly, that a fuller knowledge of these growth- 

 mechanisms will give us a clue to the principles of 

 race differentiation. 



There must be many other mechanisms regulated 

 by hormones with which we are as yet totally un- 

 acquainted. I will cite only one instance — that con- 

 cerned in regulating the temperature of the bodv. 

 We know that the thyroid and also the suprarenal 

 glands are concerned in this mechanism ; they have 

 also to do with the deposition and absorption of pig- 

 ment in the skin, which must be part of the heat- 

 regulating mechanism. It is along such a path of 

 inquiry that we expect to discover a clue to the ques- 

 tion of race colour. 



This is not the first occasion on which the doctrine 

 of hormones has been applied to biological problems 

 at the British .Association. In his presidential address 

 to the Zoological Section at Sheffield in 1910 Prof. 

 G. C. Bourne applied the theory to the problems of 

 evolution ; its bearing was examined in more detail 

 in an address to the same section by Prof. .Arthur 

 Dendy during the meeting at Portsmouth in 191 1. 

 .At the meeting of the association at Newcastle in 

 1916 Prof. MacBride devoted part of his address to 

 the morphogenetic bearings of hormones. Very soon 

 after Starling formulated the hormone theory. Dr. 

 J. T. Cunningham applied it to explain the pheno- 

 mena of heredity (Proc. Zool. Soc. London, p. 434, 

 1908). Nav, rightly conceived. Darwin's theory of 

 pan-genesis is very much of the same character as 

 the modern theory of hormones. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Camhridge. — Prof. G. H. F. Nuttall, Quick pro- 

 fessor of biology, has received from Mr. P. .A. Mol- 

 teno, of Trinity College, a letter dated October 23 

 desiring to present to the University a sum of 20,000!. 

 to provide suitable buildings and fittings for an insti- 

 tute for research in parasitology, and a further sum 

 of io,oooZ. to provide an income for the upkeep and 

 maintenance of the institute. Plans have been drawn 



