Chap. Y.] INTELLECTUAL FACULTIES. 153 



Even at a remote period lie practised some subdivision of 

 labor. 



The lower animals, on the other hand, must have their 

 bodily structure modified in order to survive under great- 

 Ij^-changed conditions. They must be rendered stronger, 

 or acquire more eiFective teeth or claws, in order to defend 

 themselves from new enemies ; or they must be reduced 

 in size so as to escape detection and danger. When they 

 migrate into a colder climate they must become clothed 

 with thicker fur, or have their constitutions altered. If 

 they fail to be thus modified, they will cease to exist. 



The case, however, is widely different, as Mr. Wallace 

 has with justice insisted, in relation to the intellectual and 

 moral faculties of man. These faculties are variable ; and 

 we have every reason to believe that the variations tend 

 to be inherited. Therefore, if they were formerly of high 

 importance to primeval man and to his ape-like pro- 

 genitors, they would have been jDcrfected or advanced 

 through natural selection. Of the high importance of the 

 intellectual faculties there can be no dovibt, for man main- 

 ly owes to them his preeminent position in the world. 

 We can see that, in the rudest state of society, the indi- 

 viduals who were the most sagacious, who invented and 

 used the best weapons or traps, and who were best able 

 to defend themselves, would rear the greatest number of 

 offspring. The tribes which included the largest number 

 of men thus endowed would increase in number and sup- 

 plant other tribes. Numbers depend primarily on the 

 means of subsistence, and this, partly on the physical 

 nature of the country, but in a much higher degree on the 

 arts which are thei'e practised. As a tribe increases and 

 is victorious, it is often still further increased by the ab- 

 sorption of other tribes." The stature and strength of the 

 men of a tribe are likewise of some importance for its suc- 



* After a time the members, or tribes, which are absorbed into an- 



