20 INTRODUCTION. 



The position, then, of the skull, the character of the vertebral 

 column, and of the pelvis, and also the great development of the lower 

 limbs, and their bearing upon the feet, shew that the erect attitude is that, 

 alone, which is capable of being naturally maintained by Man. But, again, 

 an examination of the general characters exhibited in the osseous frame- 

 work of the chest, and superior extremities, tends also to convince us, 

 that there is, as far as even these are concerned, an insuperable barrier 

 to the quadrupedal attitude. The great breadth of the chest in Man, 

 compared with its antero-posterior depth, necessarily places the scapula 

 in a dorsal situation, so that the glenoid cavity, for the reception of the 

 head of the shoulder-bone, has an obliquely lateral aspect : it is very 

 shallow ; materially differing, in this point, from the deep acetabulum, or 

 socket, for the reception of the head of the thigh-bone. Now, were Man 

 to attempt the quadrupedal attitude, the head of the shoulder-bone 

 (humerus) would be brought to bear, not against the centre of the shal- 

 low glenoid cavity, but against its sides, or edge ; and, in this critical 

 situation, the superincumbent weight would have to be sustained : but 

 the ;lax structure of the shoulder-joint, allowing freedom of motion 

 to the greatest possible extent; the distance to which the shoulders 

 are thrown apart by the clavicles ; the structure of the elbow-joint ; the 

 rotatory motion of the fore-arm on its own axis ; the arrangement of 

 the parts of the hand, in which the moveable phalanges are so largely 

 developed, and the carpus, or solid part, reduced within so small a com- 

 pass ; the position of the hand, which, instead of being at right angles 

 with the fore-arm, is continued from it in the same line, and, indeed, 

 cannot, without pain, be brought into a right angle ; all these arrange- 

 ments, while they tend to unfit the anterior extremity as an organ 

 of support, admirably qualify it for the important and dignified pur- 

 poses to which it is destined in the economy of our race. 



Of all the lower Mammalia, the Quadrumana (and among them the 

 Orang and Chimpanzee) approach, in the arrangement of their osseous 

 framework, and, consequently, in their attitude, the nearest to Man ; but, 

 inasmuch as their structure differs from that of Man, in many essential 

 particulars, so do these well-marked departures from the human type of 

 organization indicate a corresponding difference in their natural attitude ; 

 which, conformably with their intermediate organization between the 

 biped and quadruped, is neither horizontal nor erect, but oblique or 

 diagonal. The Ape tribes, however, as will be explained more fully 

 hereafter, are organized as scansorial" (or climbing) Mammalia ; and their 

 tottering posture, when they attempt the erect attitude on the ground, 

 contrasts very strikingly with their ease and activity among the branches 

 of the forest. 



The muscular forces, by which the bipedal progress, in the erect atti- 



