536 MAN'S PLACE IN NATURE 



nings no greater effort of mentality than the observation 

 that plants spring from seeds and that by putting a num- 

 ber of seeds into the ground in accessible locations one 

 will have in due time a considerable stock of food con- 

 venient to hand. No animal so far as we know can or 

 does till the soil. There is scarcely a race of men outside 

 the polar regions that fails to practice agriculture in some 

 form. The primary advantage of agriculture relates it- 

 self to the advantages of fire and clothing in extending 

 man's range. In this particular case the extension takes 

 the direction of affording him time for other occupations 

 in the intervals of food-production. Progress is born of 

 spare time. So long as every waking moment must be 

 devoted to the fundamental activities of satisfying hun- 

 ger, securing safety, and perpetuating the race, there is 

 no opportunity for progress. 



Although the ability to carry on agriculture is here 

 stated to be a strictly human characteristic, it must not 

 be forgotten that among certain kinds of ants elaborate 

 systems of crop-raising are maintained. The reason these 

 are not admitted to be of comparable importance with 

 human agriculture is that they show no signs of being 

 other than complicated instincts; they have no basis of 

 genuine intelligence, that is to say, of associated 

 memory, as is proved by the absence of adaptability in 

 their performance. Crop-raising ants can be placed in 

 circumstances where the carrying on of their regular tasks 

 is futile to absurdity, yet not the slightest modification 

 of their routine behavior is observable; the entirely use- 

 less manoeuvers are performed with the persistency which 

 characterizes instincts and distinguishes them from in- 

 telligent activities. 



Language. — In addition to the three examples of 

 mental power described above, with regard to which one 

 might question whether they require higher intelligence 

 than do some of the things regularly done by intelligent 

 animals, and yet whose possession by man and not by 



