i2 4 PHYSICAL BASIS OF CIVILIZATION 



also contributed to lengthening helpless infancy in 

 the human species, as contended by John Fiske. 

 Whether it has or not, this is certain, that from the 

 very first appearance of brute-man on earth, help- 

 less infancy must have endured in this race longer 

 than in any other. This follows as an unavoidable 

 conclusion from physical uprightness, which involves 

 a very complex and delicate co-ordination and co- 

 operation of many widely differentiated structures, — 

 bones, tendons, muscles, nerves, etc. Therefore, it is 

 possible only after all these various parts have been 

 developed by exercise into a considerable degree 

 of precision and efficiency in their adjustments. 



The arrangements subserving locomotion in most 

 other animals are comparatively simple. Very 

 little strength and precision, and but a small degree 

 of co-ordination of four very similar if not almost 

 equivalent movements, is required to enable young 

 quadrupeds to balance their bodies and move about. 

 But in man, muscles about the back, chest, abdo- 

 men, neck, and head, and in the toes, feet, limbs, 

 hips, and arms, must accurately co-operate in balanc- 

 ing the body for standing or moving about in the 

 erect attitude. And because of this degree of com- 

 plexity, this variety of co-operating organs and 

 co-ordinated muscular contractions, a higher degree 

 of precision in functioning is necessary in the human 

 race, which can be attained only by allowing a 

 longer period for development, that is to say, a 

 longer infancy. And this reasoning and this con- 



