MEAT DIET

Otago Daily Times, Issue 18768, 23 January 1923, Page 10

MEAT DIET

BASIS OF EVOLUTION. NEW THEORY PUT FORWARD. The speculations so entertainingly sec forth by H. G. Wells about the beginning of the earth, the origin of life upon it, the glacial epoch, and other great mysteries of millions of years ago, have been overshadowed somewhat by a more recent senes of speculations (says a writer in the New York Times). The nebular hypothesis, for instance, wju greatly damaged before Wells adopted it. T. U. Chamberlin’s explanation of the upbuilding of the earth and the other planets had been for many years favoured among American scientists, against the old speculation of Kant and Replace. In the last two years a new explanation, put forward by Jeans, the British astronomer, has been gaining ground. As for the beginning of life, the greatest of all mysteries, recent experiments concerning tiie power of lighr rays to build up elaborate molecules out of water and carbon dioxide have caused some zoologists to specidata on the possibility that combinations could bo elaborated in this way until they formed a living substance, the basis of all Jife. Now theories have been put forward in the last two years, and old ones ha ve gained ground, to account for the ice ages, the tropical fossils found near the Polos, the Arctic fossils found near the Equator, and for evidence of the work of glaciers in temperate regions. To explain this old mystery, Wells adopts the idea that periodic changes in (he earth’s track wound the sun put the earth in cold storage for periods of thousands or millions of years. One of the new theories holds that the earth grew' cold when it passed through a black nebula, or one of the dusty regions in space which blot out stars from many parts of the heavens. Such a_ passage would have cut of! sunlight sufficiently, according to Dr Harlow Shapley, Director of the Harvard Observatory, and reduced the temperature of the earth enough to cause glaciation. No effort has been made by Wells to fill in with detail how man was developed from his monkey-like ancestor. In the two years since his book was published, whole libraries have been published on the endocrine glands. They have been credited on speculative grounds with a large part in man’s evolution. The most spectacular development of this theory was furnished by Professor Bolk, a Dutch scientist, in an address to the Royal College of Physicians and Burgeons in England. EVOLUTION BY GLANDS. Reviewing a series of diseases of the ductless glands, he showed how one such disorder caused the growth of dark thickened patches of skin; how another produced bony growths of the hands and feet; how another caused enlargement of the jaw bones and changes of the features. In his opinion, each gland disease produced a throwback in the human constitution to an earlier apelike condition. If the function of the endocrine or ductless glands were impaired, he concluded that man would bo a leathery, hairy being, with enormous hands and feet, jutting brows, great jaws, other anthropoid features. The next step in his reasoning was that man used to be such a creature, but that he was transformed into a human by the action of the endocrine glands in modifying uis anthropoid characteristics. Some great change in the habits of our prehuman ancestors caused an increase in the activity of those glands, according to his argument. Ibis change, according to Professor Bolk. was the adoption of the meat diet. The whole monkey race to-day lives on fruit and vegetables. Out ancestors broke away from this regimen, began to kill and eat meat, and the use of concentrated food produced profound physiological changes. One of these changes, the Dutch scientist thinks, was to stimulate the ductless glands, causing them to pour out greater quantities of their chemicals, which had a modifying and refining effect, vetoing the hairy coat, the thick skin, the coarse pigmentation, and crude features of the brute supposed to have preceded man. CAUSE OF ICE AGES. The opinion, based,on some evidence, that the continents float about on the earth so that the tropics of one period might in a few million years shift to the poles, iis another guess as to the cause of the ice ages, but the prevalent theory is that some change in the heat-giving power of the sun was the chief factor. Since Wells wrote new light possibly has been thrown on the problem of man’s evolution by studies of the endocrine gland system. The Jeans hypothesis to account for the birth of the planets assumes that the sun at one time had no system of planets and that the materials which now compose the earth, Mars, Jupiter, and the rest of the planetary bodies, were part of the ball of gases and fluids which composed (ho sun. Ur Jeans proceeded on the basis that the path of the sun and that of another star had crossed each other. From our knowledge of the tide which the moon raised on the earth, he started to calculate what sort of a tide a giant bodv like another sun would raise at comparatively close range in the gas and liquids of our sun. The tremendous force of gravity exerted on fluids and vapours under such conditions would draw out a vast arm from the sun, millions of miles in length. On the departure of this disturbing neighbour the arm of matter would be dragged around under the influence of the sun and gradually condensed and shaped into planets. Such is the explanation of Dr Jeans. “COLD” THEORY OF CREATION. The Chamberlin theory is that the world never was a ball of fire, but was formed by the gradual combination of cold materials. He supposed that material diffused through space and carried along by the srui gradually formed centres of greater density. Each centre became a nucleus which kept on picking up now materials. These grew, swept up other combinations, and m the course of millions of billions of years, formed the earth and the sister planets, as they exist to-day. After being formed of cold materials, pressure might have pro duced a hot centre, if (here is such. Volcanoes arc looked on to-day by many students as eruptions on the outer skin of the earth, having no connection with what goes on beneath the crust. . The earth is somewhere between two and eight billion years old. in the opinion of scientists who discussed it before the British Association in 1921. Dr Henry Norris Russell, of Princeton, supposes that life originated in low marshy regions, half water and half land. Within the last year, the idea has been put forward that it started near the mountain tops. Supposing the earth a hot body, slowly cooling, it has been pointed out that a temperate condition necessary for life would first exist at a great altitude. The climate mighthave been- mild and water plentiful in high daces, while the oceans were still boiling and the plains and valleys superheated and steaming. , , . . , The fundamental problem of how dead matter was turned into living matter has received new light from recent research, according to the presidential address of Dr E J. Allen, recently delivered before tno zoology section of the British Association. After a technical discussion of the production of formaldehyde sugars and other substances by the treatment of water and carbon dioxide with rays of different wavelength, Dr Allen “aid: “If these results of the pure chemist are justified, thev go far toward bridging the gap which has separated the inorganic from the organic and make it not too presumptuous to hazard the old guess that, even to-day it is possible that organic matter mav lie produced in the sea and other natural waters without the intervention of living organisms.” CONTINENTS AFLOAT. The most interesting of recent discussion about the past of the earth concerns the von Wegener theory, put forth some years ago. This theory assumes that the continents and the crust of (he earth are afloat on the core of the earth. Recently the thickness of this crust has been put at seventy-one miles. Observations at Ukiab, in- California, have shown that the surface of the earth there was moving north at the rale of one foot a year. This motion of the earth’s crust has been confirmed in many other places. An effort also has been made bv von Wegener to show from records that Greenland has moved some 1700 feet within n comparatively few years. The whole face of the earth has been changed by this supposed floating of tbo continents. According to the German, some parts of the land have boon squeezed into mountain ranges by pressure from one section and resistance from another, and elsewhere continents and islands have broken away from other continents. Von Wegener has ‘constructed plastic maps to show how mountain ranges could be flattened out, certain low levels raised, islands and neninsulas fitted together. Africa dovetailed upon South America, and both drawn southward and attached to what was the continent of Antarctica. , following this theory, land might have floated, in millions of years, from hot e'imates to cold, but this would not fully account for the ice ages, because the earth cooled off during that period and no mere shift of continental arena would have produced it- The usual belief among astronomers is that the sun, Iron some unknown cause, undergoes a regular variation over long periods, being damped down for an

age and then tired up for another. The suggestion of Dr Shapley that the passage of (lie solar system through cosmic dustclouds might modify climates has received a good deal of study, because of the discovery of great areas of sky where stars are blackened out by some intercepting material.