382 BOARD OF AGRICULTURE. [Pub. Doc. 



composition to-duy enal)les us to detect many additional 

 weaknesses; l>ut, until our knowledge of the composition 

 of plants is still further increased, it will continue to be the 

 method emph)yed l)y all investigators. 



2. The Establishment of Digestion Coefficients. 



Holding fast to the work already accomplished, viz., the 

 perfection of chemical methods for determining the four 

 groups of fodder constituents, we have stilt not entirely ac- 

 complished our object ; for a nutrient is not that portion 

 determined simply by chemical analysis, but rather that por- 

 tion of the group which the animal is capable of digesting^ 

 which o;oes to the sustainins; of the vital forces and to the 

 production of l)()nc, flesh, and fat. An experiment to deter- 

 mine digestion coeflicients, briefly described, is as follows : 

 We first analyze the fodder to be fed, determining the per- 

 centages of cellulose, fat, protein and extract matter it con- 

 tains. Then we feed a certain weighed quantity of this food 

 and suliject the portion that is undigested, i. e., the solid 

 excrements, to the same analysis. Knowing now the per- 

 centages contained in the fodder before it was consumed, 

 and also the percentages undigested, the difference l)etvveen 

 the two will give ns the digested percentages, or diges- 

 tion coefficients. Of course there are many details to 

 be observed, and care to be taken, in order to obtain 

 correct results, which the worker alone can under- 

 stand. Henneberg carried on these experiments first with 

 oxen and afterwards with sheep, and they have been 

 continued at this station even up to the present time. 

 Digestion experiments were afterwards taken up by many 

 other stations in Germany, and when a sufficient numl)er 

 had been completed. Professor von Wolff" brought them 

 togcth(M- into the so-called Wolff''s tables, published every 

 yeai- in Mentzcls and Lengerke's * agricultural calendar, 

 and used in all (juai'ters of the world. L(!t me now give 

 you a practical example. How much digestible material will 

 twenty ])()unds of average English hay contain? 



* Julius Knhn has also puljlished similar compilations in his book entitled " Die 

 Zwcckraassisste Ernilhrung des llindviehs" (the most correct way to feed farm 

 stock). 



