78 The Feeding of Animxds 



in this particular, and it is found that this body does 

 not normally exist in the seed -coatings, this tissue con- 

 sisting largely of mineral matters, proteids, cellulose, 

 and gums. On the contrary, the germ and the interior 

 material deposited around it are rich in starch. To be 

 sure, wheat bran, which is now very largely the outer 

 seed-coats of the grain, has more or less, but this is 

 due to imperfect milling. It is very evident, there- 

 fore, that the term nitrogen -free extract, as applied 

 to different cattle foods, stands for greatly unlike mix- 

 tures of compounds, for we have largely starch in the 

 cereal grains and mostly other substances in the straws 

 and other coarse fodders. The importance of this fact 

 will appear in considering the digestion and value of 

 food compounds. 



Starch is an important commercial article, and for 

 this purpose is mainly obtained from corn and pota- 

 toes. It is used as human food, as a source of dextrin 

 and in other ways. By treatment with an acid, corn- 

 starch is converted into the glucose of our markets. 



The vegetable gums. — It has become evident, doubt- 

 less, during our discussion of nitrogen -free extract, 

 that a considerable portion of this class of compounds 

 consists of something else than the carbohydrates al- 

 ready noticed. For example, at the Maine Experiment 

 Station, the composition of several samples of corn 

 fodder was closely investigated. It was found that 

 the proportions of starch and sugar varied greatly, 

 mostly in accordance with the stage of growth, being 

 much more abundant in the mature plant. Even 

 with flint corn nearly ripe, not over one -half of the 



