and crude protein. We have known how to divide the pro- 
tein into two classes of nitrogen compounds, which are 
probably of very unequal value as food constituents, and, 
while we have been accustomed to speak of nitrogen-free 
extract, as though it had some definite individual character, 
we have done so with the understanding that it included 
gums, starch, sugar, etc., etc., and the same has been the 
case with the term crude fiber. We know that it contains 
cellulose and other allied compounds which differ from one 
another in composition, and probably to even a greater ex- 
tent in their physiological value. Several of these com- 
pounds give, under similar treatment, a characteristic pro- 
duct which becomes the measure of the amount of them 
present. While it is exceedingly improbable that there is 
in the hays, to be mentioned later, only one furfurol-yield- 
ing complex, I have, for the sake of greater simplicity, cal- 
culated the results obtained in terms of xylan, as this is 
probably the predominating group yielding the furfurol. 
These substances are given in the present prevailing 
method of stating fodder analyses, partly as crude fiber and 
partly as nitrogen-free extract. The former, according to 
our results, contains from one-half to three-fourths of them 
and the latter the rest. We frequently speak of the nitro- 
gen-free extract as almost equivalent to carbohydrates 
soluble in water; this custom has the merit of easy expres- 
sion and convenience. It is not our province to determine 
the relation of these constituents to the economy of the 
plant, and it does not effect our object in the least to deter- 
mine this, but simply to determine the quantity of them 
present. It seems highly probable that, as they are more 
reactive than the celluloses proper, they play a more impor- 
tant part in the nutrition of animals than these, but are in- 
ferior to the carbohydrates proper. 
We have followed in our furfurol determinations the 
method as laid down by the Association of Official Agricul- 
tural Chemists, except that we dissolved the hydrazone in 
ether alcohol. 
The samples of alfalfa hay used in these determina- 
tions were the same samples of which fodder analyses have 
been given in Bulletin No. 35 and in the early part of this 
bulletin. The results in the following table are calculated 
on dry matter. The crude fiber found in these samples 
is also given. 
