40 Home Economics and Biological Chemistry [Sept. 



followed in detail. Under the general head of alimentation we 

 study the composition, digestibility and general nutritive values 

 of typical foods. The various digestive processes are fully treated, 

 the influences of bacteria in the alimentary tract are considered, 

 and the composition of feces, as w^ell as the significance of its 

 Chief constituents, is noted. The Channels of absorption are fol- 

 lowed, and the qualities of the absorbable digestive products, as 

 well as the transformations such products undergo, prior to and 

 after their incorporation into the blood, are given due emphasis. 



In the study of alimentation and absorption it is shown, for ex- 

 ample, that food, which ordinarily consists for the most part of 

 miscellaneous masses containing many complex substances, is 

 chemically converted into fairly uniform liquid mixtures contain- 

 ing comparatively few, and relatively simple, nutrient products. 

 The Student learns that chief among the digestive products are 

 monosaccharids, mainly glucose (representing primarily the food 

 starches), glycerol and fatty acids or corresponding soaps (rep- 

 resenting chiefly the food fats), and amino-acids (representing 

 the food proteins). The Student is also taught, as clearly as pos- 

 sible in this connection, that the digestive and absorptive processes 

 are analogous, in their results, to the achievements of stone cutters 

 and masons. Stone cutters convert rock masses of various shapes 

 and dimensions into massive construction units, of a few types and 

 sizes, which masons put into harmonious relationships in the erec- 

 tion, repair, or extension of buildings on definite plans. The diges- 

 tive processes convert organic food substances, of many different 

 types and molecular configurations, into molecular construction 

 Units of a few kinds and sizes, which, in most cases, are specially 

 adapted for immediate conversion into Compounds characteristic of 

 normal blood and lymph. Various groups of cells along the absorp- 

 tive Channels actively rearrange many of these organic molecular 

 construction units into normal blood and lymph constituents of the 

 more complex types. 



The opposite phase of cellular nutrition is next brought for- 

 ward. How are waste products ehminated from the cells? What 

 are the local and systemic influences and general fate of the 

 various kinds of waste products? The gaseous eliminations having 



