No. 6. OlOFAll'rMI'^N'l' OK A(;iUClli;i'lJKIO 5f.V 



COMMERCIAL FKKDING STUFFS IN PENN- 

 SYLVANIA. 



AN INVESTIGATION BY THE DEPARTMENT OF AGUICUI.TUKE OF PENN- 

 SYLVANIA IN CO-OPERATION WITH THE PENNSYLVANIA STATE COL- 

 LEGE AGRICULTURAL EXPERIMENT STATION. 



BY WIIjLIAM FREAR, PH. D., State College, Pa. 



The chemist in his examination of cattle foods, separates them 

 into several principal groups of materials: 



1. Jloisture. 



2. AsA, the mineral matter of the food that is left when it is burned. 



3. Protein, the total nitrogenous material of the food, which is 

 assumed to be entirely composed of substances like the white of 

 egg (albumen) in their chemical and nutritive properties, and called 

 cdhumhwids from this resemblance; but, in point of fact, in many 

 foods, jiarticularly the green and immature leaf and stalk crops and 

 the root crops, a large part of the nitrogenous material is composed 

 of crystallizable substances (non-albuminoids) of quite different nu- 

 tritive value. The mature grain and stalk contain comparatively 

 little of the non-albuminoids. 



4. Fiber, the woody matter, forming the framework of plants. 



5. Nitrogen- free extract, including starch, sugars, gums, plant 

 acids, etc. This group with the fiber composes the carbohydrates of 

 the food. 



6. Pats, or more properly, the ether-extract. This is determined 

 by extracting the dry food with ether, which takes out the fat with 

 more or less of other materials; from the grain, little else; but from 

 leaves, stalks, etc., relatively large quantities of coloring matters, 

 waxes, etc. 



Before any of these substances can be used, they must be dissolved 

 by the digestive fluids of the mouth, stomach and intestines and 

 taken up into the body. This process of solution and absorption 

 is called digestion. The degree to which any of the above groups of 

 food constituents is digested depends both upon the nature of the 

 animal using the food, the nature of the individual substances of 



