952 



EXPERIMENT STATION RECORD. 



are ''used to designate, respectively, the carbohydrates and more or 

 less condensed portions of tbe fiber," and not to represent definite 

 chemical compounds. 



The food (bran) and feces from a digestion experiment witli a steer 

 made at the Maryland Station' were examined by the author, using the 

 above method. The amounts of the different carbohydrates of the food 

 and feces and their coeflicients of digestibility are given in the follow- 

 ing table: 



Coefficients of digestibility of carbohydrates of bran by a steer. 



Soluble 

 carbohy- 

 drates. 



Ill fond 



In feces 



Coefficients of digestibility.. . 



Per cent. 



7.2 



.7 



96.9 



Starcb. 



Per cent. 

 17.7 



Free pen- 

 tosans. 



Per cent. 

 17.5 

 18.7 

 66.2 



Cellulose. 



Lignin 

 and allied 

 sub- 

 stances. 



Per cent. 

 8.5 

 20.2 

 24.8 



Total 

 carbohy- 

 drates. 



Percent. 

 11.6 

 23.2 

 36.7 



Per cent. 

 62.5 

 62.8 



Undeter- 

 niiued. 



Percent. 

 4.U4 

 2.00 



For the sake of comparison the coefficients of digestibility of bran 

 obtained at the Maryland Station ' are given in the following table: 



Coefficients of digestibility of bran by a steer. 



In food 



1 u feces 



Coefficients of digestibility 



Nitrogen- 

 free 

 extract. 



Crude 

 fiber. 



Per cent. 

 55.59 

 41.93 

 76.08 



Per cent. 

 10.96 

 23. 47 

 32.21 



Total 

 carbohy- 

 drates. 



Per cent. 

 66.55 

 65.40 



Protein. 



Per cent. 

 20.49 

 11.04 

 82.96 



Etlier 

 extract. 



Per cent. 



6.92 



12.52 



42. 73 



Ash. 



Per cent. 



6.05 



11.04 



42. 21 



"We sec from the above that the digestibilities of the insoluble carbohydrates 

 range from 25 to 100 per cent. The nitrogeu-free extract with a mean digestibilitj- of 

 76 per cent is composed of substances whose percentage digestibilities vary from 100 

 to less than 40. Even in the case of the crude fiber the. digestibility of one of tlie con- 

 stituents considerably exceeds that of the other. It must be borne in mind in this 

 connection that the group of lignin and similar substances is divided by the current 

 metbods, part being included in the nitrogen-free extract and part in tlie crude fiber." 



Methods of analysis of barnyard manure, J. H. Vogel {Ber. 

 Ver.^. Stat. deut. landiv. Ges.l894-'95,pp. 11-14, 2:^-25, Jigs. 10). — Samples 

 of from 5 to 10 kg. are usually taken and kept in rubber sacks until 

 prepared for analysis. For the latter purpose the material is finely 

 divided by means of a chopping knife and thoroughly mixed. For tlie 

 determination of nitrogen 100 gm. of the finely divided manure is 

 placed in a wide-necked IJ liter flask, 125 to 140 cc. (according to the 

 moisture content of the manure) of concentrated sulphuric acid added 

 and the whole allowed to stand over night. Eight to nine grams ot 

 mercury is then added and the digestion commenced, the flame being 

 kept quite low at first to prevent foaming. The digestion is usually 

 complete in from 4 to 5 hours. The contents of the flask are then 

 taken up in water, thoroughly mixed, and the volume made up to 



' Maryland Sta. Bui. 41 (E. S. E., 8, p. 1004). 



