60 ON THE PLACE OF MAN IN THE SCALE OF BEING. 



Characteristics of Man. 



62. We shall now review, somewhat in detail, the distinctive characters 

 that separate Man from those animals which present the nearest approach to 

 him in general structure and aspect. These may be advantageously classified 

 according to their ohvious purposes ; and the first series we shall notice, con- 

 sists of those by which Man is peculiarly adapted to the erect attitude. On 

 examining his cranium, we remark that the condyles, by which it is articu- 

 lated with the spinal column, are so placed, that a "perpendicular let fall from 

 the centre of gravity of the head would nearly fall between them, so as to be 

 within the base on whi&h it rests. The foramen magnum is not placed in the 

 centre of the base of the skull, but just behind it, in order to compensate for 

 the greater specific gravity of the posterior part of the head, which is entirely 

 filled with solid matter, whilst the anterior part contains many cavities. 

 There is, indeed, a little over-compensation, which gives a slight preponde- 

 rance to the front of the head ; so that it drops forwards and downwards, when 

 all the muscles are relaxed. But the muscles which are attached to the back 

 of the head, are far larger and more numerous than those in front of the con- 

 dyles ; so that they are evidently intended to counteract this disposition ; and 

 we find, accordingly, that we can keep up the head for the whole day, with 

 so slight and involuntary an effort, that no fatigue is produced by it. More- 

 over, the surfaces of the condyles have a horizontal direction, when the head 

 is upright ; and thus the weight of the skull is laid vertically by them, upon 

 the top of the vertebral column. If these arrangements be compared with the 

 position and direction of the occipital condyles in other Mammalia, it will be 

 found that these are placed in the latter much nearer to the back of the head, 

 and that their plane is more oblique. Thus, whilst the foramen magnum is 

 situated, in Man, just behind the centre of the base of the skull, it is found, in 

 the Chimpanzee and Orang Outan to occupy the middle of the posterior third ; 

 and, as we descend through the scale of Mammalia, we observe that it gradu- 

 ally approaches the back of the skull, and at last comes- nearly into the line of 

 its longest diameter, as we see in the Horse. The obliquity of the condyles 

 differs in a similar degree. In all Mammalia except Man, their plane is 

 oblique ; so that, even if the head were equally balanced upon them, the force 

 of gravity would tend to carry it forwards and downwards. In Man, the angle 

 which they make with the horizontal is very small ; in the Orang Outan it is 

 as much as 37 ; and in the Horse, their plane is vertical, making the angle 

 90. If, therefore, the natural posture of Man were horizontal, he would in 

 this respect be circumstanced like the Horse ; for the plane of his condyles, 

 which is nearly horizontal in the erect position, would then be vertical ; and 

 the head, instead of being nearly balanced in the erect position, would hang 

 at the end of the neck, so that its whole weight would have to be supported 

 by some external and constantly-acting power. But for this, there is neither 

 in the skeleton, nor in the muscular system of Man, any adequate provision. 

 In other Mammalia, the head is maintained in such a position, by a strong 

 and thick ligament (the ligamentum nuchae), which passes from the spines of 

 the cervical and dorsal vertebrae to the most prominent part of the occiput ; 

 but of this there is scarcely any trace in Man. In the horizontal position, 

 therefore, he would have the heaviest head, with the least npwer of support- 

 ing it. 



63. The position of the face immediately beneath the brain, so that its front 

 is nearly in the same plane as the forehead, is peculiarly characteristic of 

 Man ; for the crania of the Chimpanzee and Orang, which approach nearest 

 to that of Man, are entirely posterior to, and not above, the face. It should be 



