8*6 



NA TURE 



[December 23. 1922 



more akin to man and anthropoids in a structural 

 and evolutionary sense than is Tarsius — in spite of 

 this and other unexpected human likenesses possessed 

 by the latter. To account for the irregular distribution 

 of certain characters possessed by man and Tarsius, 

 Prof. Wood Jones has put forward the claims of owl- 

 eyed Tarsius to pose as one of man's near relatives. 



The relationships of Tarsius to man, says Dr. Gregory, 

 " are plainly very indirect and must be traced back- 

 wards along gradually converging lines to the primitive 

 tarsioid stocks, which gave rise at different times 

 and at different places to the higher groups of primates." 

 As it has a bearing on such problems as the irregular 

 distribution of the human mode of placentation 

 among the primates, Dr. Gregory quotes with approval 

 a principle enunciated by Dr. Henry Fairfield Osborn 

 in 1908 and "familiar to all close students of mammalian 

 phylogeny, namely, that identical characters are often 

 developed by divergent descendants of a common stock." 

 To the master morphologists of our studenthood days 

 such a statement would have sounded heretical 

 or metaphysical, but to those who are familiar with 

 the complex mechanism of hormones, which regulate 

 the growth of diverse structural elements so that they 

 are moulded to serve a common functional purpose, 

 this statement, made by one who has given a lifetime 

 to the observation of fossil forms, has become of easy 

 acceptance to those who are studying the development 

 and growth of living forms. Our difficulties of account- 

 ing for the composite make-up of the human body 

 and of that of his congeners, the anthropoid apes, 

 will disappear once we have mastered the . growth 

 mechanisms which lead to the creation of structural 

 modifications and the suppression and perhaps resuscita- 

 tion of old features. 



The reviewer has merely noted here the chief con- 

 clusions which years of careful toil have permitted 

 Dr. Gregory to formulate concerning man's origin. 

 The main value of the work he has now published 

 is to provide students of the higher mammalian forms 

 with an indispensable dictionary for the interpretation 

 of dental hieroglyphics. Out of a restricted alphabet, 

 Nature has fashioned teeth into a most elaborate and 

 significant language. How these elements are manipu- 

 lated so as to provide a profusion and variety of 

 dental forms we do not know but it is clear to the 

 least initiated that upper and lower teeth have to lie 

 so fashioned, while still embedded in the gums, that 

 when they come into place in the jaws they will fit 

 each other just as a key does its lock. There must 

 be a correlating mechanism at work to harmonise the 

 bite of opposing cusps. Of this Dr. Gregory is fully 

 cognisant, but we regret that he has not abandoned 

 the confusing system of naming the cusps of molar 

 NO. 2773, VOL. I io] 



teeth introduced by Dr. Osborn. In this system the 

 names given to the cusps of upper molar teeth are 

 reversed when applied to the cusps of lower teeth — 

 a method with all the perplexing attributes of a reflected 

 image. Besides, as Dr. Gregory has frankly admitted, 

 the system, which has served a good purpose in its 

 time, is really founded on an erroneous interpretation. 

 Another small and personal grudge the reviewer may 

 also give vent to — the introduction of the new-fangled 

 nomenclature for the old and well-established generic 

 names we have hitherto been accustomed to give to 

 apes and monkeys. But the reviewer's last words 

 must be those of admiration and of thanks for a 

 standard work. A. Keith. 



A Reflective Observer. 



A Philosopher with Nature. By Benjamin Kidd. Pp. 

 vii + 211. (London: Methuen and Co., Ltd., 1921.) 

 6s. net. 



M 



R. BENJAMIN KIDD was a keen observer of 

 Nature, particularly interested in the prob- 

 lems of animal behaviour and all that throws light on 

 evolution. This volume is a collection of his essays ; 

 with the exception of the first two, which deal very 

 attractively with the birds of the Severn estuary, they 

 have been previously published in serials. But in 

 collected form they are very welcome. In all cases 

 there is a characteristic reflective note : What is the 

 deeper significance of this or that occurrence ? The 

 primitive language, among birds for example, is un- 

 doubtedly a language of the emotions, but it is inter- 

 esting to notice that it is often a kind of lingua franca 

 understood even by widely different species. The 

 young of the mallard, which has probably been the 

 most universally hunted creature on earth, nestle on 

 the observer's bare feet without the slightest instinct- 

 ive fear. " You take one of them in your hand, and 

 this heir of the ages of the blood-feud shows no fear of 

 you, even tilting its little beak to look inquiringly in 

 vour face ; evidently thinking no evil, to all appear- 

 ance hoping all things and believing all things, but 

 certainly quite willing to take you on your merits for 

 good or evil entirely without prejudice." The mother 

 bird is on a tussock near by, " chattering with emotion, 

 every feather quivering with excitement. The hold 

 of the Great Terror of Man is upon her. In a few days, 

 nay, in a few hours, she will have taught it to them, 

 and they will have passed irrevocably into another 

 world." Character is a product of " Nature " and 

 " Nurture." 



An interesting experiment was made with a colony 

 of humble-bees which Mr. Kidd kept on his window- 



