REPORT ON GRASSES AND FORAGE PLANTS. 187 
similate it, than upon the chemical composition of such food. To illus- 
trate: Celiulose and starch have absolutely the same percentage compo- 
sition of carbon, hydrogen, and oxygen; but while the value of starch as 
food is universally conceded, the worthlessness of cellulose is as uni- 
versally admitted. The reasonis that starch when taken into the stom- 
ach is readily digested and taken into the blood, while cellulose resists 
any such chemical change and is eliminated from the body unchanged. 
Those constituents of animal food which are composed of carbon, 
hydrogen and oxygen only are known under the general name of ear- 
bohydrates, but there is great difference between these as to their rela- 
tive nutritive value. Some of them are readily digested, as starch and 
the sugars, while others are apparently incapable of digestion, as cellu- 
lose. Still others of these compounds appear to have a certain value, 
which at the present is not well defined nor generally accepted. Among 
these constituents are gum, the so-called amylaceous cellulose, and the 
alkaline extracts of the foregoing analyses. 
As to gum, certain experiments appear to show that it is capable of 
digestion—at least some kinds of gum. It is at least true that in the 
laboratory it is found subject to changes closely analogous to those of 
starch, that is, it may be converted into one of the sugars. So, too, of 
the compound given in the analyses as amylaceous or starchy cellulose. 
This substance appears to stand in its chemical properties, as its name 
implies, midway between starch and cellulose. Although not so readily 
acted upon as starch, it is yet far more readily affected than cellulose; 
and since in the digestive apparatus of the herbivora it is subject to 
action somewhat analogous to those conditions which effect its conver- 
sion into sugar in the laboratory, it seems not unlikely that such changes 
do ensue during the process of digestion, and that this compound pos- 
sesses a nutritive value not far interior to true starch. 
The compound present in the grasses and given under the name of 
alkaline extract is still more obscure, and its nutritive value as yet not 
established. In composition it is closely analogous te the starchy com- 
pounds; and since by mild chemical reagents it is proved to enter into 
solution, it appears not improbable that it possesses a nutritive value 
not far removed from the well-known members of the group of ecarboby- 
drates to which it belongs, viz., starch and sugars. 
As will be seen, then, there yet remains, even in the consideration of 
our best known grains and grasses, a wide field for further investiga- 
tion; and although tbe results of chemical analysis seem to indicate the 
results which practical experiments in feeding shall establish, these 
practical results remain undetermined. 
METHOD OF ANALYSIS OF GRASSES. 
1, Estimation of water.—Three grams of the finely powdered grass were 
dried as rapidly as possible at a temperature of 105°-110° ©. ‘The loss 
of weight was taken as water. 
2. Estimation of oil and wax.—The previously dried three grams of 
grass were extracted with ether, sp. gr. .722, in the apparatus figured in 
Proceedings Am. Chem. Soc., Vol. 2, No. 2, p. 85, which, wilh some 
modifications, seems to be admirably adapted for this work. The ether 
was carefully evaporated at a low heat, and the residue weighed as oil 
and wax. This residue was then extracted with cold ether and the 
portion undissolved estimated as wax. 
*3. Lstimation of sugars, &c.—The residual grass from treatment with 
ether was percolated with warm 85 per cent. alcohol untill 200 ¢. ¢. were 
