THE REACTION TO FOOD 34 1 



of known nutrient principles which just suffice to complete 

 the food in question and form an adequate diet. This system 

 is known as the "biological method" for the analysis of a food- 

 stuff. We now have a great body of knowledge based upon 

 the application of this procedure to all our more important 

 natural foods. 



Many kinds of grazing animals subsist well solely upon 

 leaves of grass or other forage crops. The importance of 

 the leafy type of vegetable in the diet of the rice-eating 

 peoples cannot be overestimated. Because of the density 

 of population, milk-producing animals are not kept in the 

 rice-eating regions so these people have never had a supply 

 of dairy products. Their only food of animal origin is eggs, 

 poultry and pork, which are eaten somewhat sparingly, 

 but in some places considerable amounts of fish are available. 

 People on such a dietary regimen are very successful in 

 their physical development and compare in the most favored 

 districts with the best specimens of the human race any- 

 where to be found. 



A third type of diet which is satisfactory is found in use 

 in the dryest regions of the world. On the margins of the 

 Sahara and Arabian deserts, and in the great dry belt 

 extending across Asia from Arabia to Mongolia, the inhabit- 

 ants subsist only through the conversion of pasturage into 

 human food through the agency of flocks and herds. Here 

 the only article fit for human consumption which is likely 

 to be available in abundance is milk, which ordinarily 

 sours quickly because of the contamination of the containers 

 with remnants of sour milk and the absence of means of 

 refrigeration. In Arabia the typical diet of the native 

 consists mainly of sour milk, but this is supplemented with 

 a small amount of barley bread, dates, and with meat 

 approximately once a month. Even under the trying condi- 

 tions of desert life people live and maintain surprising 

 vitality on such a simple regimen. There are certain char- 

 acteristics about the diet of people in the great centers of 

 culture in the north temperate zones, which include the 

 United States, Canada, and Central Europe, that tend to 

 induce malnutrition. The significance of this could not be 

 appreciated until research on quality in foods and the 



