DARWINISM IN THE NURSERY. 685 



for observing can see for himself, this has been accounted for from 

 the fact that the thighs are flexed against the abdomen during the 

 hitter part of intra-uterine life. But from analogy with other 

 young creatures, such as those already mentioned and young 

 birds, we find that the pre-natal position has little or no influence 

 in decreeing the habitual attitude of the limbs after birth, and it 

 seems to me more logical and reasonable to trace this also to a 

 prior state of evolutionary development. 



Man is, when standing erect, the only animal that has the 

 thigh in a line with the axis of the vertebral column, and among 

 his nearest congeners in the animal world the flexed state of 

 the femoral articulation is natural and constant. As we go down 

 the scale the angle between the thighs and trunk diminishes, until 

 it reaches the right angle characteristic of most quadrupeds. I 

 speak here of the attitude adopted when the animal is at rest 

 upon its legs, for during sleep there is in many cases a curious re- 

 version to the position occupied in embryonic life. Thus we see 

 that a bird roosting with its head " under its wing," and the legs 

 drawn up close to the body, offers a decided resemblance to the 

 chick in the Qgg. 



I have noticed that young children, when old enough to shift 

 their limbs, very seldom sleep in any but the curled-up posi- 

 tion ; and that as often as not, when unhampered by clothing or 

 other artificial restraints, they sleep in the same attitude as do 

 many quadrupeds, viz., with the abdomen downward and the 

 limbs flexed beneath them. I am told that negro mothers and 

 nurses in the West Indies invariably lay their charges down to 

 sleep on their stomachs, and that this custom is also common in 

 various parts of the world. Adult man is, I believe, the only ani- 

 mal who ever elects to sleep upon his back. Some of the lower 

 savages seem to sleep comfortably on occasion in a crouching 

 position with the head bent down upon the knees, just as all the 

 common tribes of monkeys do. Among the quadrumana it is not 

 until we come to the platform-building anthropoid types that we 

 find a recumbent position habitually taken during sleep. The 

 young orangs and chimpanzees that they have had at the Zoologi- 

 cal Gardens slept with the body semi-prone and with the limbs, 

 or all except one arm, which was used as a pillow, curled under 

 them. This is exactly the position voluntarily adopted by eighty 

 per cent of children between ten and twenty months old which 

 I have had opportunities of watching. I was told by the attend- 

 ants at the Zoological Gardens that no ape will sleep flat on his 

 back, as adult man often does. 



It would be very interesting to get exact observations as to 

 the habits of all the lower tribes of men with regard to sleeping, 

 for it is a point upon which a great deal would seem to depend, if. 



