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Supplement to ''Nature'' August i8, 1923 



many generations come to have human hands and 

 arms — then the evolution of the human hand was a 

 comparatively easy problem. At no time of his life 

 did Huxley believe that the effects of use or disuse did 

 become hereditary. In 1890 he wrote:* " I absolutely 

 disbelieve in iisf-inhcritance as the evidence now 

 stands." 



Having tlius rejected the only known means by which 

 useful or purposive modifications of the body can be 

 brought about, we turn with some degree of curiosity 

 to his lecture in Glasgow ^ on the evolution of the hand. 

 The exact title which he gave to his discourse was 

 " On the Teleology and Morphology of the Hand." 

 This is how he approached the problem of adapta- 

 tion : 



" To be a teleologist and yet accept evolution, it 

 is only necessary to suppose that the original plan was 

 sketched out — that the purpose was foreshadowed in 

 the molecular arrangements out of which the animals 

 have come." Then tM^elve years later (in a letter to 

 Romanes in 1888) he w^rote*: "It is quite conceiv- 

 able that every species tends to produce varieties 

 of a limited number and kind, and that the effect 

 of natural selection is to favour the development of 

 some of these, while it opposes the development of 

 others, along their predetermined line of modification." 



Huxley as an Evolutionary Predestinarian. 



Thus it will be seen that Huxley, on the evidence 

 then at his disposal, had come to the startling con- 

 clusion that the shaping or controUing forces which, 

 in due season, were to give man his hand, lay latent in 

 the germ-plasm of that simian stock which ultimately 

 blossomed into human and anthropoid shapes. The 

 evidence which forced Huxley to take up the position 

 of an evolutionary predestinarian must have been 

 indeed cogent. Only a few years previously (1868), 

 Sir Richard Owen had given utterance to a somewhat 

 similar belief, when he wrote : ' " Generations do not 

 vary accidentally in any and every direction, but in 

 preordained definite and correlated courses." Huxley, 

 as was afterwards the case with Weissmann, believed 

 that the creative machinery of evolution lay in the 

 womb of the germ-plasm. 



Modern Predeterminists. 



Manifestly, if the evolutionary fate of man is already 

 determined by the properties of his germ-plasm, as 

 Huxley believed, it is a truth of the utmost consequence 

 to medical men. We cannot, if this be true, in any 

 way control the future of humanity, except by the 



• Life and Letters, by his son, Leonard Huxley, 1900, vol. 2, p. 268.^ 



• Life and Letters, vol. i, p. 456. I have been unable to obtain any 

 published account of this lecture save that given by Mr. Leonard Huxley 

 in the " Life and Letters." 



• Life and Letters, vol. 2, p. 188. 



' Anatomy of Vertebrates, vol. 3, p. 808. 



application of Darwin's law of selection. Man's des- 

 tiny lies hid in the potentialities of his germ-plasm. 

 Huxley's belief is widely shared by modem students 

 of evolution. No one has had better opportunities 

 of noting how evolution has worked in shaping higher 

 mammals during the Tertiary period than Dr. H. 

 Fairfield Os bom, of the American Museum of Natural 

 Histor>'. He finds ample evidence of a " definite or 

 determinate origin of certain new characters, which 

 appear to be partly a matter of hereditary disposition . " *» 

 He finds that evolutionary tendencies, like that which 

 leads to the formation of horns and antlers, may lie 

 latent in an ancestral stock, and only become manifest 

 at subsequent times and in different ways in certain 

 of the descendants of that stock. That evolutionary 

 manifestations of this kind have taken place in the 

 evolutionary history of the higher primates — the group 

 to which man belongs — there can be no doubt. 



In recent times this conception of evolution working 

 out its effects in predetermined directions has been 

 forcibly suggested by Bateson. In his presidential 

 address to the British Association in Australia in 19I4 

 he expressed himself thus : 



" If then we have to dispense, as seems likely, with 

 any addition from without, we must begin seriously 

 to consider whether the course of evolution can at 

 all reasonably be represented as an unpacking of an 

 original complex which contained within itself the 

 whole range of diversity which living things present. 

 ... At first sight it may seem rank absurdity to 

 suppose that the primordial form or forms of proto- 

 plasm could have contained complexity enough to 

 produce the diverse types of life." 



In this passage Bateson plainly suggests that the 

 machiner}' of evolution has proceeded on its way, 

 untrammelled by any outward circumstance, right 

 from the first appearance of living protoplasm. We 

 have here the doctrine of evolutionary predestination 

 stated in its most extreme form. Whether such a 

 belief as this of Bateson is well founded or not, it shows 

 us that one who has given a lifetime to the study of 

 variation and of heredity is of opinion that the evolu- 

 tionary machinery which has given man his brain, 

 his hand, his foot, and his posture has worked out its 

 effects undisturbed by the surrounding conditions of 

 life. In brief, functionally wrought modifications have 

 had no part in shaping the human body.* 



Before proceeding to set out the evidence concerning 

 the nature of the machinery which shapes man's body, 

 there is another opinion, akin to that of Huxley, which 



• The Origin and Evolution of Life, 1918, p. 278. In this work the reader 

 will find references to literature bearing on predeterminism in evolution. 



• It is unnecessary to give here a list of the men who have concluded that 

 plants and animals tend to vary in definite directions, whatever be the 

 circumstances in which they are placed. The evidence relating to this 

 matter has been very ably summarised in recent times by E. S. Russell, 

 Form and Function, London, 1916 ; and by PVof. R. Anthony , " Le 

 Determinisme et I'Adaptation Morphologique," Archives de Morphologic, 

 Paris, 1922. 



