BABIES AND MONKEYS. 375 



crease of necessary muscles have occupied the somewhat vacant 

 space. 



Other characters, however, tell the same tale of adaptation. 

 The proportion in length between the arms and legs of a baby 

 when first born is very different to what obtains later in life. To 

 use a somewhat incorrect phrase, the legs are in an undeveloped 

 condition, and they have to grow quicker, in proportion, than the 

 arms. The greater development of the arms in proportion to the 

 legs in a newborn infant points to ancestors who used the arms 

 more than the legs for sustaining the weight of their bodies, and 

 this would mean that they lived an arboreal life. Dr. Louis Rob- 

 inson, in an interesting article,* has fully illustrated the reason 

 for superior arm-power in infants by his experiments on the hang- 

 ing power of babies. 



In the method of using its hands the baby shows to the full its 

 descent from arboreal ancestors. When it wishes to take hold of 

 anything, alike a glass or a flowerpot, it does not, like an adult, 

 put the hand round it, or even put the thumb inside to use as a 

 lever. On the contrary, it places all the fingers inside, makes no 

 use of the thumb, and clasps the rim of the flowerpot between 

 the fingers and the palm of the hand. This is exactly the action 

 which would be acquired from arboreal ancestors : in going from 

 bough to bough they would take their hands palms first, and 

 would strike from above downward, grasping the bough with 

 the fingers. Such is the action of an infant picking up a cup. So 

 little use have some monkeys made of the thumb that abortion 

 has resulted ; and in the most arboreal species of monkeys known 

 the fingers have grown together because the whole hand was used 

 merely as a grasping-hook. It is probably from our ancestors' 

 excessive use of the hands in bough-grasping that our babies in- 

 herit a certain inability to move the fingers with freedom, or to 

 extend the hand, especially if the least degree cold. The power 

 to extend the fingers perfectly straight is oftentimes not obtained 

 by children at six or seven years of age. 



Turning to the characteristics of an infant's feet and its habits 

 of movement therewith, much instruction may be obtained by 

 noticing these matters. Darwin observed the infant's ability to 

 twist the sole sideways in a straight line with the inner part of 

 the leg, a necessary ability to a tree-climbing animal; and he 

 cited it as evidence of monkey ancestry. Considering how little 

 an adult can move his or her toes, the power of movement of 

 these organs by an infant is something remarkable, and it points 

 to some ancestral environment of very different character from 

 that which surrounds man at the present day. The big toe the 



* Nineteenth Century, November, 1891, p. 838. 



