74 "fHE COMING OF MAN 



tion. Some reptiles swam with paddles, others flew with bat- 

 like wings. Some ran on four legs or strode on two, using the 

 front pair somewhat Hke hands. They became at home on 

 land, in water, and in the air. They conquered and possessed 

 the world partly by brute force, partly by speed and agility. 

 They showed the possibilities of a marvellously developed mus- 

 cular system guided by a very economically constructed brain. 



From flat worms upward progress has been focused chiefly 

 on the muscular system. Its development has dragged with 

 or after it that of all the other systems, even of nerves, sense- 

 organs and brain. Keen sense-organs have been a great asset 

 but mainly as a part of the steering apparatus. Thus far 

 the race has been to the swift and the battle to the strong, as 

 was to be expected. The bird carried the tendency to its 

 logical conclusion. It became a flying-machine; and this 

 aerial adaptation has left its stamp on every organ of the body. 

 In swiftness of locomotion, in keenness of sense especially of 

 sight, the hawks and carnivorous birds hold the record. 



It is a somewhat disappointing story. Millions of years of 

 painful struggle and combat, and infinite experiment, and the 

 result is something less efficient than an automobile with eyes 

 instead of lamps or an aeroplane careering through the air. 

 It reads like Falstaff's bill at the inn. We say: " One half- 

 penny worth of bread to this intolerable deal of sack! " If 

 movement was all we wanted, there was plenty in the delirious 

 electrons. 



There is nothing particularly striking or interesting in prim- 

 itive mammals. In breadth of experiment, in adaptation and 

 general development they seem to lag behind birds and rep- 

 tiles. They are certainly not precocious. Their energy of 

 evolution seems to be turned aside, drawn off, in some direction 

 hard to follow. They have the advantage over reptiles of 

 maintaining a constant comparatively high temperature of the 

 body. This stimulated the activity and development of the 

 organs somewhat in proportion to the complexity and in- 

 stability of their chemical composition, especially of the proto- 



