{8 The Descent of Man. Part 3 



and changed their habits many times, before they reached their 

 present homes. 64 The early progenitors of man must also have 

 tended, like all other animals, to have increased beyond their 

 means of subsistence they must, therefore, occasionally have 

 been exposed tc a struggle for existence, and consequently to the 

 rigid law of natural selection. Beneficial variations of all kinds 

 will thus, either occasionally or habitually, have been preserved, 

 and injurious ones eliminated. I do not refer to strongly-marked 

 deviations of structure, which occur only at loug 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, 65 

 to incessant variability. If then the progenitors of man inhabit- 

 ing any district, especially 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 movement for gaining subsistence, or for defending themselves, 

 would on an average survive in greater numbers, and procreate 

 more offspring than the other and less well endowed half. 



Alan 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 that any other highly organised form : and 

 all others have yielded before him He manifestly owes this 

 immense superiority to his intellectual faculties, 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 : 66 " a psychological 

 " analysis of the faculty of language shews, that even the smallest 

 " proficiency in it might require more brain power than the 

 " greatest proficiency in any other direction. 5 ' He has invented 

 and is able to use various weapons, tools, traps, &c, 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 neighbouring fertile islands. He has discovered the art of 



64 Latham, ' Man and his Migra- "classed in any of the above 

 Lsns,' 1851, p. 135. " groups." These muscles differ 



65 Messrs. Murie and Mivart in even on the opposite sides of the 

 then 'Anatomy of the Lemuroidea' same individual. 



(' Transact. Zoolog. Soc. vol. vii. 66 Limits of Natural Selection, 



1869, pp. 96-98) say, "some muscles 'North American Review,' Oct 



u are so irregular In their distribu- 1870, p. 295. 

 ■* tion that they ciunot be well 



