Attainment of the Upright Posture of Man

IN his recent paper entitled ``Fifty Years Ago''<sup>1</sup>, Sir Arthur Keith tells how, when in Siam in 1890, he became impressed by the similarity in muscular and visceral adaptations shown by the hand-swinging gibbon and bipedal orthograde man. The gibbon suspends its body in an upright posture by hanging from its hands; man maintains his upright posture by standing on his feet. It was, therefore, an easy step to assume that the brachiating gibbon had paved the way to human uprightness. The story of this assumed transition is most graphically told in Sir Arthur Keith's little book ``The Human Body'', and it has become the creed of what W. K. Gregory of New York terms ``the orthodox school''. This brachiating hypothesis of the origin of man's upright attitude has been accepted by practically all English-speaking anthropologists and palæontologists. We may cite the Romanes Lecture of 1928 by Prof. D. M. S. Watson, the works of the late Sir Graf ton Elliot Smith and many others in its support. This orthodox school, as represented by Gregory, claims that the brachiating habit is ``a necessary introduction to the upright posture of Man'', and man is defined by the same authority as ``a made-over brachiator adapted to life on the ground'' (``Man's Place among the Anthropoids'', 1934).