THE SECRET OF LIFE.

Otago Witness, Issue 3614, 19 June 1923, Page 59

THE SECRET OF LIFE.

SIR ARTHUR KEITHS ILLUMINAT IXG STORY 01 EVOLUTION.

‘'•Since the publication of the ‘Origin of Species’ no single discovery has thrown so much light on the machinery of evolution as that made by Professor Starling and Sir William Bayliss that the living units of the body had a hitherto unsuspected method of communicating with each other by means of chemical messengers or hormones. The untold billions of Jiving units of the human body not omy used the circulating blood to bring them their supply of food and eliminate their refuse, but utilised the same stream lor the conveyance of their postal traffic. Each unit of the body could make its in dividual wants known and could be duly informed of the needs of that part of the community with which it had to deal. “It was this complex postal or hormone system that Nature used in shaping new forms of man and beast. Everyone was familiar with the alterations produced by the elimination of the seed glands, but it had recently- been found that there layover each kidney a small body fashioned out of the same substance as that which formed the seed glands. Sometimes this took on a malignant growth in childhood, with the result that the child, whether male or female, developed premature manifestations of manhood. This could be cured by a surgical operation.” “Charles Darwin, in tile discovery which changed the whole thought of mankind, sowed that the development of the human race was due to a process of evolution,” says the Morning Post. “The Darwinian theory, like all new ideas, was opposed at first, but to-day there are few educated persons who do not accept its truth, subject to recent modifications. There was a difficulty, however, present in the minds of many, in what appeared to be the cessation of the evolutionary process. If there was evolution in the pact, why is it not observable in the present? If is true that a part, if not the whole, of the apparent anomaly might be due to a too limited conception of the time required for the processes of Nature, to whom a thousand years is as one day. -—The Answer.—“But the conclusive answer is supplied in the recent biological discoveries, of which Professor Sir Arthur Keith gave so illuminating an account at the Royal Institution. “The answer is that the process of evolution is constantly and demonstrauly at work in the embryo. The evolutionaryforce (in whatever it may consist) s exercised during the pre-natal period. "Now that discovery, which is of quite extraordinary significance, modjfi.es the previous theory, which was that during the pre-natal period and in infancy the r.'iman being passed rapidly and, as ; t were, automatically-, through all its earlier stages of evolution. Sir Arthur Keith demonstrates the fact that the struggle to fit the new being for its environment begins and is practically completed before birth. He likens the process to the larger spectacle in progress in a city, in which the spirit of change and the spirit of resistance to change, are perpetually m conflict, and in which the result is development. —A Great Discovery.— “Sir Arthur Keith affirms that the most important discovery in biology made since Darwin is the discovery- of Professor Starling and Sir William Bayliss that various organs in the body- possess the power, by- means of chemical constituents called honnones, to affect one .another. “The hormones may be roughly com pared with messages delivered by a postal system. For instance, the three glands, pituitary-, thyroid, and supra renal, quite definitely regulate certain processes; and if the action of a gland be abnormal, corresponding abnormality will result, such as the giant or the dwarf. “Equally remarkable is the discovery that the pineal gland, which was once a third eye in a remote ancestor, has become in man a gland buried deep in his brain and regulating growth. “Again, in the case of certain tissues impinging on other tissues, the first have the power of creating a new organ out of the second. Such is the process by means of which the lens of the eye is formed. Other organs which, as man developed, were no longer required remain but as vestiges, such as the tail, which is also shed in embryo by the anthropoid apes. The palatal nose, again, was eliminated in the embryo when the development of the hand made tho palatal nose unnecessary. Instances might be multiplied. And Sir Arthur Keith affirms that the same machinery is at work in the brains and mind of the embryo. “But if the operation of the machinery is becoming more accurately understood, its motive power remains as heretofore a profound mystery. The processes of evo lution are obviously intelligent; or, should we say, directed by an intelligence of the highest order? In what does that intelli genee consist? It may, of course, be observed th\t the intelligence makes mistakes, and, indeed, perfection is hardly ever achieved. But side by side with that reflection should be considered the fact that what w-e call disease, as Sir John Bland-Sutton has shown in his hook on the subject, is also subject to the law of evolution. —Wliat is Man?— “It has been suggested by the distinguished French investigator, Dr Geley, that biological research should be conducted, not upwards from the origins of man, but downwards from man as he is to-day. Dr Geley seeks the answer to the immemorial question, ‘Wliat is man?’ rather in the realm of mind than of matter; and regards the process of evolution as being essentially a development from unconsciousness to consciousness. If

Dr Geley’s theory be valid. Sir Arthur Keith’s admirable contributions to the sum of knowledge must be regarded as being themselves a definite advance in evolution. The pity is that they cannot be instilled into the whole mind of mankind at once, instead of gradually infiltrating the general intelligence,” concludes the Morning Post. Sir Arthur Keith’s lectures, on which the Post comments, were on the kind of machinery- used by Nature in the evolution of the human body and brain. —How it is Done.—• “The present situation, he said, was that students of modern evolution were certain that Nature in recent geological ages had succeeded in breeding man and ape out of a common ancestral stock, but were still uncertain as to the exact means employed. There was one safe guiding principle in research work that the machinery, whatever it was, was still silently working in our bodies, and in the growing child Nature was using the identical machinery she had used in effecting her miracles of evolution. Unquestionably the machinery of growth was the machinery of evolution, and for this reason every effort was being made to find out how the growth of the human body was regulated. “Since the death of Darwin something had been learnt of the way in which the parts of the eye were brought together during he formation of the embryo. The recording part of the eye sprang as a bud from the brain, while the lens was produced from the over-lying skin. If the brain ‘bud’ was moved so as to lie against another part of the embryonic skin, it caused the new area, of skin to form a lens, thus showing that one part of the embryo could control the growth of a neighbouring part. —The Worth of Brain.— “There was no more striking fact concerning the evolution of the human body-," said Sir Arthur Keith, “than the fact that while man possessed an unique power of using his larynx and tongue for speech and the muscles of his face for all shades of expression, yet these muscles were just those found in the highest apes, slightly differentiated, but with no new element introduced. Man’s pre-eminence was due solely to the rise and overwhelming growth of his brain. .The Huxley-Owen controversy- as to whether man’s brain was built on the lines of that of the chimpanzee had long ago been answered in the affirmative, but it remained to be discovered liow it was that man’s brains had so far outstripped those of the ape. “What was known was that by- the sixth month the controlling portions ol the brain were already expanded so as to overshadow all primitive parts. These elements consisted of billions of microscopic living units which had a marvellous power of arranging themselves. The power that young nerve and muscle units possessed in this respect was no more and no less wonderful than the faculty of the wandering white blood corpuscles that could find out when a piece of scavenging work needed their attention. “The task in front of those studying the machinery- of development was a long one. They- had to investigate the habits of the various units of the embryonic body with the same attention as that given to the nature and ways of live animals. It would eventually be known, however, how man came by the peculiar properties of his brain and mind when such studies had been completed,” concluded Sir Arthur.