HORMONES AND OSTEOBLASTS

Sun (Auckland), Volume III, Issue 670, 23 May 1929, Page 8

HORMONES AND OSTEOBLASTS

Sir,— Mr. Eeuben E. Dowle is in error wlien he imputes to me the desire to evade the issue of design or contrivance so evident in all living forms. In reply, I can do no better than quote from Sir Arthur Keith’s latest book. .Darwinism and What It Implies”: * * -Ift us see how medical men account for the wonderful examples of design and contrivance which so -abound m man’s body. There is in the human thigh-bone, as Dr. Paley was well aware, just as clear evidence of engineering and architectural skill as are to be found in any watch. Such evidence of design is not so mvsterious to us as it was to Dr. Paley because, thanks to the modern improvement of the microscope, we have come to know something of the ‘bone-build-ers concerned; great armies of mere specks of living protoplasm, known technically as ‘osteoblasts.’ . . . AV'e know that they are sensitive to* the strains and stresses which fall on them and respond by laying down material so as to meet and carry all transmitted forces. We know that they are . .. controlled in their activities in sevfJu 1 ays ’ Particularly by substances . V 1 them from other parts of the body, substances now named “horar© learning the nature of the signals and impulses which set t^ € L m to work. . . There is no duality of function in living matter. An osteoblast is both architect and mason in the very essence of its being. ... If l am asked to explain how the* cells which build our bones come to be endowed with such marvelldus faculties, l reply that I know of only one way of throwing light on the problem. Thai rs the way we owe to Charles Darwin: it he who taught us how to trace the history of such cells—to follow their evolution back to their oldest and simplest forms. . . . For modern students the ‘thinker’ and the ‘thought,’ the ‘directing intelligence,* do lie outside living matter . . . but are of the essence of its constitution.”

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Mr. Dowle’s contention regarding gaps occurring in intermediate forma shows a misconception of the conditions under which fossil forms are preserved. The preservation of animal f remains in the earth’s strata is con-* ' tingent upon a rare combination of circumstances, so that it would be pos-. sible for whole species and orders to live and die without Leaving a trace oC their existence. Moreover, geology ill but in its youth, and scarce a fraction of the earth’s fossil resources havd been tapped. Palaeontology provides only one of the fields for evolutionary research, and the evidence so far ac* cumulated points all in one direction—* to the truth of the law of organic evoi i lution. A.E.C. i i