Physical Evolution of Man 575 



weaves, shapes, sews, and puts on his clothes; digs, cuts, or 

 hews down material for his home; prepares it often elaborately, 

 pieces it together, and roofs in the whole; fashions and places 

 lights for its illumination. He internally decorates it with 

 materials at times of the most delicate aad elaborate hand 

 workmanship; he prepares the soil, sows, waters, reaps, garners, 

 and distributes his grain, straw, fruits, etc. ; he fashions instru- 

 ments of musical harmony, of mechanical skill, of space-pene- 

 trating power, of microscopic exploration, of wholesale destruc- 

 tion. He so operates on the body of his neighbor — surgically 

 taking it apart, and placing it together again — as to convert 

 that body truly into a living machine; he catches, tames, pens 

 up, and uses the animals below him as he wills, to ride on them, 

 to be drawn by them, and to use them in many other ways for 

 his purposes. Like the beaver he builds dams, digs canals, 

 and drains or floods countries. He puts together machines 

 that chain and store heat, chemical energy, mechanical energ>% 

 and electricity. He expands even on all of the above in end- 

 less manner, so that he can correctly proclaim himself '*Lord 

 of creation." 



How then has he succeeded in this, compared even with the 

 sagacious dog or elephant? Simply and solely because his 

 forelimbs in relation to the brain, and on the principle of action 

 and reaction, have gradually become highly perfected for all 

 of the above work. But it may be objected that some deep 

 and mysteriously acting agency caused increase of the brain 

 substance, and that the latter, sending efferent impulses to the 

 limbs, caused these to become molded with increasing delicacy 

 to wider and wider uses. This might seem plausible, did we 

 only trace one evolving line of animal life which showed such, 

 and that one culminating in man. 



But, as already demonstrated, the cephalopods, spiders, ants, 

 beavers, elephants, and dogs, as well as monkeys, all exhibit 

 along diverse lines the same specializing modifications that 

 develop yari passu with diverse activity in circum-cephalic 

 organs and with increasing and condensing brain^substance. 

 Such would strongly suggest that cooperative action and reac- 



