508 LAWS OF MULTIPLICATION. 



temperature. Both in their qualities and quantities the 

 foods they live on are unlike; and the supply is here regular 

 and there very irregular. Their expenditures in bodily action 

 are extremely unequal; and even still more unequal are 

 their expenditures in mental action. Hence the factors, 

 varying so much in their amounts and combinations, can 

 scarcely ever have their respective effects identified. Never 

 theless there are a few comparisons the results of which may 

 withstand criticism. 



366. The increase of fertility caused by a nutrition that 

 is greatly in excess of the expenditure, is to be detected by 

 contrasting populations of the same race, or allied races, 

 one of which obtains good and abundant sustenance much 

 more easily than the other. Three cases may here be set 

 down. 



The traveller Barrow, describing the Cape-Boers, says : 

 &quot; Unwilling to work and unable to think,&quot; ...&quot; indulging 

 to excess in the gratification of every sensual appetite, the 

 African peasant grows to an unwieldy size ; &quot; and respecting 

 the other sex, he adds &quot; the women of the African peasantry 

 lead a life of the most listless inactivity.&quot; Then, after illus 

 trating these statements, he goes on to note &quot; the prolific 

 tendency of all the African peasantry. Six or seven children 

 in a family are considered as very few; from a dozen to 

 twenty are not uncommon.&quot; The native races of 



this region yield evidence to the same effect. Speaking of 

 the cruelly-used Hottentots (he is writing a century ago), 

 who, while they are poor and ill-fed, have to do all the work 

 for the idle Boers, Barrow says that they &quot; seldom have more 

 than two or three children; and many of the women are 

 barren.&quot; This unusual infertility stands in remarkable con 

 trast with the unusual fertility of the Kaffirs, of whom he 

 afterwards gives an account. Rich in cattle, leading easy 

 lives, and living almost exclusively on animal food (chiefly 

 milk with occasional flesh), these people were then reputed 



