54 THE DESCENT OF MAN. 



at long intervals of time, but to mere individual differences. 

 We know, for instance, that the muscles of our hands and 

 feet, which determine our powers of movement, are liable, 

 like those of the lower animals,* to incessant variability. 

 If then the progenitors of man inhabiting any district, es- 

 pecially one undergoing some change in its conditions, were 

 divided into two equal bodies, the one-half which included 

 all the individuals best adapted by their powers of move- 

 ment for gaining subsistence, or for defending themselves, 

 would on an average survive in greater numbers, and pro- 

 create more offspring than the other and less well endowed 

 half. 



Man in the rudest state in which he now exists is the 

 most dominant animal that has ever appeared on this earth. 

 He has spread more widely than any other highly organized 

 form: and all others have yielded before him. He mani- 

 festly owes this immense superiority to his intellectual fac- 

 ulties, to his social habits, which lead him to aid and defend 

 his fellows, and to his corporeal structure. The supreme 

 importance of these characters has been proved by the final 

 arbitrament of the battle for life. Through his powers of 

 intellect, articulate language has been evolved; and on this 

 his wonderful advancement has mainly depended. As Mr. 

 Chauncey Wright remarks :f "a psychological analysis of 

 the faculty of language shows, that even the smallest pro- 

 ficiency in it might require more brain power than the 

 greatest proficiency in any other direction/'' He has in- 

 vented and is able to use various weapons, tools, traps, etc., 

 with which he defends himself, kills or catches prey, and 

 otherwise obtains food. He has made rafts or canoes for 

 fishing or crossing over to neighboring fertile islands. He 

 has discovered the art of making fire, by which hard and 

 stringy roots can be rendered digestible, and poisonous roots 

 or herbs innocuous. This discovery of fire, probably the 

 greatest ever made by man, excepting language, dates from 

 before the dawn of history. These several inventions, by 



* Messrs. Murie and Mivart in their "Anatomy of the Leinuroidea " 

 ("Transact. Zoolog, Soc.," vol. vii, 1869, pp.* 96-98) say, "some 

 muscles are so irregular in their distribution that they cannot be well 

 classed in any of the above groups." These muscles differ even on 

 the opposite sides of the same individual. 



f Limits of Natural Selection, "North American Keview," Oct- 

 1870, p. 295. 



