HOW DO WE LIVE AND GROW? 17 



relation to nitrogen fixation and cell division. Regardless of the 

 amount of sunlight, if the soil is poor we will not get much protein, 

 nor minerals, nor vitamins. Poor soils primarily produce woody 

 plants, strongly dependent on potassium, topheavy with carbohy- 

 drates, and to various degrees indigestible. Try living on sawdust. 

 It is high in fuel value, but not for you. Termites depend on certain 

 protozoa in their digestive tracts to pre-digest wood for them. Even 

 if you could digest it, it would probably not provide sufficient pro- 

 teins for your body-building needs. It has had to rely on air and 

 water for its bulk, while soil has played a very minor part. 



Legumes are plants which indirectly add nitrogen to the soil. This 

 is accomplished by certain bacteria living in nodules on the roots. 

 These bacteria have the ability to change atmospheric nitrogen into 

 protein-like nitrate compounds. The presence of these compounds 

 insures for the legume plant a supply of protein building material. 

 When the plant dies a part of the nitrogen (in the roots) remains in 

 the soil. Crop residues above the surface may add more nitrogen as 

 decay proceeds. Future plants may use them. If a grazing animal 

 eats young, vigorous, growing, leguminous plants, it is guaranteed a 

 good supply of body building protein. (Older, senile plants lose 

 much of their earlier value.) However, legumes, such as clover, alfal- 

 fa, and soybeans, must have a generous supply of calcium; and so, 

 great areas of eastern United States must have lime applied to the 

 soil in order to grow them. To put it another way, most of the orig- 

 inally forested area needs lime, and probably other fertilizers, particu- 

 larly phosphorus, because the woody vegetation itself is evidence of 

 lower fundamental fertility than the grasslands. This is especially 

 true of coniferous forests. 



Since animals need from plants both energy factors and growth 

 factors, we must insist on food which supplies both, and in the proper 

 proportion. It is basic that our state of health, nutritionally speak- 

 ing, depends heavily on the quality and variety of the proteins we 

 consume. We shall have more to say about this later. 



Sparkplugs of Life. It was suspected about 1800 and proven 

 around 1905 that no animal can live on a diet consisting only of pure 

 protein, fat, and carbohydrate. In 1885 the Japanese removed beri- 

 beri as a devitalizer of their navy by altering the diet of sailors. Spe- 

 cifically, they cut out most of the polished rice, an energy food de- 

 ficient in vitamin BI and other vitamins, replacing it with barley and 

 other foods. 



In 1926 vitamin BI was isolated, and 10 years later it was manu- 

 factured synthetically. Today the study of vitamins is a science in 

 itself. 



Feeding vitamins to plants became a public fad a few years ago, 

 and geraniums from coast to coast were dosed with growth stimu- 

 lators (regulators). As with most such fads there was a scientific 

 basis for it. The only reason, however, for feeding vitamins to 

 plants is that the soil being used is infertile. Give the plant a soil 

 well stocked with all the necessary minerals in available form, and 



