96 SCIENCE PROGRESS 



that look most like intelligence. But the beaver begins to 

 build a dam in his house from any kind of unsuitable objects, 

 such as boots or brushes, and this although there is no water 

 in the place. 



Secondly, the metabolic scheme investigated by Rubner, 

 and already referred to, is an indication of abundant food and 

 the leisurely evolution of man. He had both food and, easy 

 conditions of life, and perhaps in consequence his reason is 

 the precise antithesis of the instincts of the beaver and the 

 penguin, for reason must be correlated with freedom. 



The absence of organs of attack and defence, the non- 

 development of the special senses, the non-growth (that is the 

 apparent retrogression) of the bones of the face, and the great 

 toe of the female foot, all indicate safety. This toe is relatively 

 as well as actually smaller in woman. As this toe may be 

 called the chief organ of running, one would have expected 

 this method of escape to have been very highly developed in 

 those who were less able to fight. 



In addition, as old age approaches, all the bones become 

 thinner, lighter, and more fragile. The skull alone loses about 

 two-fifths of its weight. Female skulls are thinner and lighter 

 than male, but heavier in proportion to the weight of the rest 

 of the skeleton (i :6 as compared with i : 8). The brain grows 

 very rapidly in the early years of life, and attains its maximum 

 weight before the age of twenty, that is before the bones are 

 complete. All these facts may be taken to indicate safe sur- 

 roundings. For as the brain became more important as regards 

 survival, it has been thrown more and more upon its own 

 resources for safety, instead of being protected by a case like 

 that of the gorilla. 



How THE Brain took Command 



For the past six thousand years there is evidence that the 

 brain of the Mediterranean race has altered remarkably little, 

 just as the bones of the little toe were as atrophic then as now. 

 But there has been a remarkable change in the mind of man. 

 Certain facts are known which show that the normal brain is 

 acting perhaps more definitely than ever as the chief selective 

 organ. Mentally defective children have small heads, usually 

 much below the average size for the age. In one form of 

 idiotcy the child of European parents has the Mongolian head 

 and features. The normal child exhibits the desire to talk 

 very early in life ; that is, speech seems to have become almost 

 instinctive. 



To review the successive stages by which the human brain 

 has acquired the power to command : When the little insecti- 



