26o SCIENCE REMAKING THE WORLD 



and as yet its practical application has but barely begun. 

 The economic and hygienic benefits which we may rea- 

 sonably anticipate are incalculable. We must remem- 

 ber that the food crops produced by a country are not 

 determined by nature (though writers often seem to 

 imply this) but by the relative demands for the different 

 things which any given farm can produce. The farmer 

 in the long run will employ his land and labour and dis- 

 pose of his crops in whatever way he finds most profit- 

 able and this in turn will depend upon what the con- 

 sumer demands in the market and the relative prices 

 which he (or she) is willing to pay. As fast as consum- 

 ers come to understand that fruits and vegetables and 

 milk are worth more and that meats and sweets are* 

 worth less than has been hitherto supposed, and show 

 this knowledge by shifting the emphasis of their de- 

 mands from meats and sweets to fruits, vegetables, and 

 milk, just so fast will more fruits, vegetables, and milk 

 be produced because they will thus become the crops 

 that pay the farmer best. 



For instance, when a normal American corn crop has 

 been harvested and all the demands of human consump- 

 tion, of industry, of seed for the next crop, and of feed 

 for the farmers* draft animals have been met, there re- 

 main in the hands of the farmers of the United States 

 over a billion bushels of grain to be turned into extra 

 meat or into extra milk according to which "the mar- 

 ket," that is, the consumer, makes it more profitable 

 for the farmer to produce. Increase in the milk supply 

 need not be entirely at the expense of a decreased meat 

 production, but even if this were true the production of 



