November, 1928 



EVOLUTION 



Page Seven 



— that is like the evolution of millions of jears which is recorded 

 in the rocks. Every man at the beginning of his life had a fish- 

 like structure, and later a reptile-like structure. Much later he 

 was a hairy, ape-like creature. His career of nine months in 

 his mother's womb is like a swift moving-picture of the progress 

 that the fossil record says his ancestors went through in the 

 course of half a billion years. 



A careful thinker might be cautious and slow about believ- 

 ing the fossil record in the rocks; for it is not complete and it 

 might be misleading. A careful thinker might hesitate about 

 the record that is reeled off in every embryo — if it was alone 

 in the world and no other evidence told the same story. But 

 what should the most wary thinker decide when he finds that 

 rocks and embr.vos tell the same history? 



Make the case vivid to yourself and get the force of it by 

 supposing that the two lines of proof were revealed to two men 

 on opposite sides of the world. Suppose that a Russian geologist, 

 after ten years of study, had been able to map all the vast pile 

 of knowledge of fossils that it has taken thousands of men two 

 centuries to accumulate. .*\nd suppose that an Australian phys- 

 ician could have learned in the same ten years the whole great 

 fund of knowledge of embryos that thousands of physiologists 

 have acquired by a century of toil. Each of these men would 

 marvel and be wary. They would not want to run any risk 

 of being ridiculed by envious rivals for hasty conclusions. But 

 suppose that they happened to meet each other and compared 

 notes. Could they any longer distrust the evidence that came 

 through their two pairs of eyes? The specialists in many depart- 

 ments of the study of life have been comparing notes in that 

 way for the past fifty years. They have unanimously decided 

 that the combination of proofs is absolutely convincing. If they 

 are wrong, the world is a senseless whirligig. If they are right, 

 the world is an orderly and rational place. 



VII. What Blood Proves 



If a witness tells a falsehood in a courtroom, and if honest 

 witnesses can then be found who will, one after another, tell 

 what facts they know, the falsehood will be disclosed. But if 

 a witness tells the whole truth, no other truthful witness exists 

 under the whole heaven who can contradict any particle of 

 the truth. 



If evolution had been false, every recent discovery in geology 

 and medicine would have contradicted evolution. The theory 

 would have died long ago. But the fact is that no recent 

 discovery of science contradicts evolution. The more new 

 knowledge we acquire, the more witnesses we have to the truth 

 of evolution. 



The latest and most dramatic proof comes from the blood 

 of animals. It has long been known that blood confirms one 

 of the strangest parts of the evidence from the rocks — that birds 

 are descended from reptiles. The warm-blooded feathered 

 creatures, so unlike reptiles in appearance and temperature, have 

 in their veins the tell-tale evidence of who their ancestors were. 



Twenty-five years ago an English chemist learned how to 

 cultivate in a rabbit's blood an anti-toxin that would give an 

 unmistakable reaction when the blood of a horse was mixed 

 with it. Blood from a relative of the horse, such as a mule or 

 zebra, would also give the reaction, but a slighter one. Blood 

 from a more distant relative, such as a cow, gave a much slighter 

 reaction. A long series of most rigorous experiments was made 

 with the blood of many sorts of animals. 



Now blood is a more essential part of an animal's make-up 

 than a skeleton is; it reveals family likenesses much more surely. 

 The evidence from blood proves conclusively what man's nearest 

 relative is: it is the chimpanzee. Thus evolution, already proved 

 beyond doubt, has been proved once more. 



Scientists at Work — Wm^ K* Gregory 



By HoR.ACE Elmer Wood, II 



THE man in the street would probably place Professor VV. K. 

 Gregory by remembering the newspaper account of a recent 

 controversy in which he stood on the side of Darwin and the 

 ape-man, as opposed to Professor Osborn's advocacy of an as yet 

 undiscovered dawn-man. This controversy, however, is merely 

 the by-product of the most recent of a long series of investiga- 

 tions covering the last quarter of a century. 



Dr. Gregory's work is morphological, rather than experi- 

 mental. It involves the careful comparison of all available 

 relevant specimens and data, noting resemblances and differences. 

 Following this first stage of observation, one or more possible 

 explanations of the facts are developed, what is known as a 

 working hypothesis, or if more than one, multiple hypotheses. 

 (It is the hypothesis which the late William Jennings Bryan 

 stigmatized as "merely a guess"). This hypothesis is then tested 

 out on the data, including, if possible, additional m.aterial besides 

 that on which it was founded. If it still stands the test, it may 

 be accepted, tentatively, its degree of probability resting on the 

 amount and kind of evidence. It must still, of course, stand up 

 under the criticism of other scientists, working in the same or 

 adjoining fields, before it can be regarded in any sense, as 

 accepted. That Dr. Gregory's extensive work usually does stand 

 up is the basis of his scientific standing. 



The doctor's thesis, in the sciences, usually is a relatively 

 modest piece of research, an article involving a relatively limited 

 problem, undertaken, in most cases, in a painstaking, but often 

 slightly amateurish fashion. It is characteristic of Dr. Gregory 

 that, for his doctor's thesis, he wrote ''The Orders of Mammals", 

 If covering the structure and interrelationships of all the major 



groups of mammals. This is still, nearly twenty years later, 

 the standard book on the subject. In such a period, most scien- 

 tific work is either disproved, relegated to the stacks as unim- 

 portant, or completely absorbed in the march of science. 



His studies on the comparative anatomy and evolution of 

 the vertebrate, skull and limbs represent another high-light. 



Students are looking forward eagerly to the appearance of his 

 promised book "The Face from Fish to Man", which will sum- 

 marize the main stages in our evolution. One such summary 

 view appears on the cover of this issue. 



There is nothing to thrill the tabloid press in a careful, 

 day in and day out, comparison of the crown pattern of the 

 teeth of one individual or species with another, until each eleva- 

 tion and depression has its own personality, and can be traced 

 through its changes from one geological level to another. Yet 

 it is just these studies which have enabled Dr. Gregory to furnish 

 the final links and corrections in the story of the evolution of 

 the teeth of mammals as a group, and of most lines of mammals, 

 man included. This has led to his work on the general problem 

 of the evolution of man — in which field he is easily the leading 

 American authority. 



It is noteworthy that Dr. Gregory is a specialist in several 

 widely separated fields, any one of which would usually furnish 

 a life-time employment for an able man. His linking together 

 of previously unconnected, though logically interrelated fields, 

 has knitted together zoology and paleontology, and emphasized 

 the common heritage of such diverse vertebrates as mud-iish 

 and revivalist. 



In addition to the preparation of his large number of valu- 

 able publications. Dr. Gregory has time to be Curator of Com- 

 parative .■\natomy in the American Museum of Natural History. 

 More recently, as Curator of Fishes, in addition, he has been 

 organizing the new "Hall of Fishes". He is also Professor of 

 Vertebrate Paleontology at Columbia University. It is, in the 

 long run, a fair test of a teacher to ask who his students are. 

 A surprising number of leading younger scientists in the fields of 

 zoology and paleontology studied under Dr. Gregory. 



Henshaw Ward, in an article in number six of this journal, 

 described an instance (the Hesperopithecus problem) illustrating 

 Dr. Gregory's scientific integrity. To those who know him, it 

 is a question whether this, or his unfailing understanding and 

 kindliness, is the more outstanding feature. 



