FORCING INTELLIGENCE 73 



Thus, the incentive supplied by the erect stature 

 is, by itself, sufficient to account for the emer- 

 gence from variations, by selection, of quite an 

 intelligent type of two-footed, upright creatures, 

 much more competent to battle for existence against 

 living antagonists than earlier generations were, 

 but it does not explain the existence of a creature 

 so enormously in advance of every other in intelli- 

 gence as to acquire undisputed supremacy on earth 

 and the control of those inexorable forces of' nature 

 which, although they were once the merciless mas- 

 ters of every living thing, our ancestors included, 

 are now our tools and slaves to serve us as we choose. 

 To account for this other causes must be searched for. 



When looking at specimens of nude art, one is 

 often impressed with the grace and dignity of the 

 human form in the upright attitude. Oblivious of 

 the efforts and pains it costs babies, invalids, and 

 tired people to maintain this position, the mind, at 

 such times, seems inclined to dwell only on the nat- 

 ural ease and unconcern with which it comes to 

 healthy persons. Indeed, those unfamiliar with 

 anatomy may perhaps be surprised to learn that the 

 muscles, tendons, bones, nerves, etc., concerned in 

 maintaining this attitude constitute a mechanism 

 of higher complexity and greater adaptability than 

 any found among the higher mammals below man. 

 This wonderful adaptability of motions and conduct 

 of the human organism to the rarest and most del- 

 icate mutations in the environment becomes most 



