188 Kansas Academy of Science. 



which the compounds consist. The physiological relations of these com- 

 pounds must also be known for any adequate study of their relation to 

 nutrition; that is, we must know how they are affected by the digestive 

 agents, and what possibilities the absorbed products of digestion present 

 to metabolism, the complex physical and chemical processes that accom- 

 pany the activities of living things. It need scarcely be said that we are 

 not in possession of such complete knowledge of even one food substance. 

 The purpose of investigations in nutrition is to explore unknown or little 

 known areas in this field, in the hope that something will be found that is 

 of benefit to man in one way or another. 



The simplest expression of the composition of a food substance in- 

 cludes the proximate principles water, ash, protein, carbohydrates, and 

 fat. This is of much service in spite of its incompleteness and indefinite- 

 ness. Better statements embody more details cencerning the ash, protein, 

 carbohydrates or fat. Nearly always in the case of cattle feeds the fiber 

 of the carbohydrates is separately stated, and the remainder placed under 

 the heading of nitrogen-free extract, which really includes several classes 

 of substances. The protein of the conventional statement is also a com- 

 plex mixture of compounds, varying greatly in value, and in the mixtures 

 found in different foods differ greatly from each other. The ash is the 

 residue left after burning a food as completely as possible at a low tem- 

 perature and is entirely different from the substances present originally. 

 It contains metals, phosphorus, sulphur, etc., which were to a consider- 

 able extent constituents of organic substances in the food. The relative 

 amounts of these elements, as well as the total quantities, give an insight 

 into the dietetic adaptability of a food. These data can be learned only 

 by detailed analysis of the ash. 



The fat of foods as ordinarily determined is also an impure extract 

 containing substances that are not fats, and usually several different 

 fats. This sketch may serve to give an idea of the extreme complexity 

 of foods and of the total inadequacy of the usual simple statements of 

 their composition. 



One of the most noticeable nutritional features of corn is the fact that 

 both the grain and the stalk possess definite value. This is also true of 

 wheat, oats and barley, but in these cases the straw is of little value. 

 With the sorghums, to which belong not only sweet sorghum, but kafir 

 corn, milo maize, feterita, etc., there is also notable value in both the 

 grain and the stalk. 



The corn plant may be utilized in several fundamentally distinct ways 

 which may be mentioned without detailed consideration. If the corn is 

 planted chiefly for grain and is permitted to come to maturity and the 

 grain is husked out, the remainder is properly designated as corn stover, 

 although often called corn fodder. Technically corn fodder is a crop 

 produced by thicker planting, from which the ears are not removed. 

 Such a crop is also available for conversion into excellent silage. In 

 addition to these standard means of utilizing the stalks of corn, to a cer- 

 tain extent corn stover is finely shredded and converted into a product 

 which can be conveniently stored under cover and fed to stock at better 

 advantage, in that it is consumed more completely, and handled more 

 conveniently. 



