ANALYSIS OF CROPS. 255 



and dilute sodium hydrate will effect the solution of all matter 

 which could be removed in the digestive processes of an 

 animal ; it evidently cannot yield any really satisfactory results. 

 Moreover, the amount of the "fibre" obtained depends very 

 much upon the state of subdivision of the material and other 

 circumstances, and the residue obtained often contains nitro- 

 genous substances. 



Non-nitrogenous extractives. This item, like all those ob- 

 tained by difference, is liable to the accumulated errors of all 

 the direct determinations, some of which, e.g., the fibre, are 

 probably very great. 



According to Stone" the results obtained by the Weende 

 method are very incorrect. He examined specimens of wheat 

 and maize, both by the usual conventional methods and by de- 

 termining the various carbohydrates actually present. Some 

 of the results by the two methods are given below. 



Air-dry material (per cent.) : 



N-free 

 Water. Ash. Fat. Fibre. Protein. extract. 



Winter wheat... 6'28 2-14 1-83 2-85 14-68 72-22 

 Spring wheat ... 8-55 1-43 2-00 2-77 14-22 71-03 

 Maize meal ...12-43 1-51 3-80 2-35 11-60 68-31 



Under the last column (obtained by difference) it is generally 

 assumed that starch, digestible cellulose, and sugars are in- 

 cluded. 



By actually determining the percentages of the various 

 carbohydrates, Stone obtained the following numbers : 



Winter wheat. Spring wheat. Maize meal. 



Cane sugar 



Invert sugar 



Dextrin 



Starch 



Pentosans 



Cellulose 



36-76 34-60 43-82 



It is thus evident that 35 or 36 % in the case of wheat and 

 about 24-5% in the case of maize of the whole material is not 



* Bulletin No. 34 (1896), Office of Experiment Stations, U.S. Dept. of Agriculture. 



