SOME POSSIBLE CRITICISMS ANTICIPATED 159 



case of small, rapidly breeding species, which rear several 

 hatches of young yearly, the principle is traceable, as we 

 have seen, with individuals in confinement ; but in this 

 case instinct will play the most important part, deter- 

 mining how many batches of young shall be reared 

 annually. They will rear fewer batches when food is scarce 

 and a larger number when food is plentiful. These free- 

 breeding types are able to recuperate their numbers 

 with extreme rapidity when circumstances again become 

 favourable after a bad season. They thus occupy a 

 middle position between those lowly types for which 

 asexual reproduction in enormous numbers when circum- 

 stances are favourable is best, and those higher types 

 whose interests are best served by a regulated sexual 

 reproduction. 



In the case of man, Spencer's remarks bear a remote 

 resemblance to what actually does happen. Generally 

 speaking, the supply of food in human society depends 

 on the number of individuals who work to produce it. 

 When the population rises or falls, the food supply, other 

 things equal, rises or falls also. But as, on the theory set 

 forth here, the amount of food is only one of the factors 

 which affect fertility, a well-fed population may be highly 

 fertile, or an indifferently fed population only moderately 

 fertile, fertility depending not merely upon the quantity 

 of food, but upon the effects of the environment as a 

 whole. 



Spencer's suggestions appear to have been in some 

 measure realised when the factory system was first intro- 

 duced into England. The lower standard of living led 

 to an increased birthrate. The workers were compelled to 

 send their children into the factories in order to supple- 

 ment the earnings of the family The employers used 

 these children to lower wages still more. The result was 



