22 JOURNAL OF THE 



THE DETERMINATION OF CRUDE FIBER. 



BY W. A. WITHERS. 



This was begun to ascertain, if possible, some of* the causes of 

 the discrepancy in results obtained by different (chemists for 

 crude fiber. The samples were Timothy hay and cotton seed 

 meal. They were not extracted with ether previous to treat- 

 ment with alkali and acid, as is customary in ordinary analyses. 

 Except when so stated, the solutions used were IJ per cent. 

 H2SO4, and IJ per cent. NagO solutions, the time of boiling 

 30 minutes, and the results in per cer»t. calculated on the dry 

 sample. 



The following questions were considered : 



1. Amount of NagO neutralized. 



By titration before and after treatment, an average of 5 dif- 

 ferent determinations gave an equivalent of .114 grams NogO 

 neutralized by Timothy hay for every gram of substance taken, 

 showing that only a very small portion of the NagO added enters 

 into chemical combination, and part of this is in the saj^onifica- 

 tion of the fat which would usually l)e extracted with ether. 



2. Sulphuric acid neutralized. 



Residues from Timothy hay, after treatment with Na^O solu- 

 tion, were taken. It was found that for each gram of substance 

 originally taken, .01 gram of H2SO4 was neutrah'zed, showing 

 that the H2SO4 does not enter into chemical combination at all. 



3. Effect of different strengths of NagO solution. 



Tliis was tested on Timothy hay with tiie following results: 



Time of treatment 45 minutes. 1^ hours. 



Na20 (srams) used per gram of) ^ g^ j 27 1.27 ].00 



substance / 



r:«.67 35.2(5 33.34 35.06 



Residues -^33.28 35 3G 33.70 35.30 



(^ ... ... 33 88 



Average 33.48 35.31 33.04 35.18 



Differenceduetodifferentstrengths ) , o.> 1 zt 



e \j r\ i ..• i" 1.00 1.04: 



ot JNazO solution j 



