544 THE CHANGING WORLD 



sary. The big toe, which in apes and babies diverges laterally 

 from the second toe, straightened and lengthened in adult man into 

 an efficient organ of support. In quadrupeds this responsibility is 

 thrown mainly on the middle toe, which in such animals as horses 

 becomes the only line of contact with the ground. 



One of the farthest reaching results of uprightness was the emanci- 

 pation of the arms from bearing the weight of the body in locomotion. 

 This freedom allows the hands, with opposable thumbs, to be em- 

 ployed in exploratory touch, in defense, and in taking hold of things. 

 The hinged wrist of man, with the rotating radius, increases the 

 availability of the grasping hand, so that it can be used in a great 

 variety of positions. Thus, instead of an organ specialized for a 

 single purpose, like the hoof of a horse, or the wing of a bat, the hand 

 remained fortunately a generalized structure capable of many uses. 

 Bats are mammals that are able to fly, but at the price of losing their 

 hands. Dr. Hooton, the anthropologist, in contrasting the foot and 

 hand of man, happily describes the foot as a "specialist," and the 

 hand as a "general practitioner." 



The many adjustments resulting from erect posture are by no 

 means confined to the skeleton. The pathologist, whose business 

 it is to seek out the weak spots in the human frame and to discover 

 the causes of human ills, has a great light shed upon his problems 

 when he remembers that man is still in the making, and that his 

 remote ancestors went about on all fours. 



The Greatest Wonder in the World 



The human brain is the greatest wonder in the world, for through 

 it alone are all the other wonders made known. It is the brain that 

 above all else is responsible for man's evident superiority over every 

 other creature, since intelligence, rather than brute strength, is the 

 greatest winning factor. Other parts of the bodily mechanism may 

 gain more perfect elaboration in various animals than in man, but 

 the human brain in its evolution has easily outstripped all other 

 anatomical achievements. 



The marvelous details of the rise of the nervous system with the 

 brain are a story for the comparative anatomist to tell elsewhere. 

 It would fill a very bulky volume, for the dawn of the mind, the most 

 wonderful of all dawns, is also the most engaging episode in the whole 

 evolutionary pageant. Moreover, only an animal with a human 

 brain can realize anything about it. 



