Ly 
pound or albuminoid, viz, besides having carbon, hydrogen, and oxy- 
gen, it also contains considerable nitrogen and a little sulphur or 
phosphorus or iron or other substances, thus forming albumen, whose 
chemical constitution is expressed by the approximate molecular 
fommula. Cragg Ni Os.0,, or by weight C 53, H 7, N 16, O 22, Sel 
per cent. Possibly this molecular formula is more properly written 
3(C,,H,.N,O,), plus the addition of sulphur compounds such as to 
make the whole become as before written. Mulder supposed that a 
certain substance which he called proteine, and whose composition is 
supposed to be C,,H,,N,O,,, 1s the basal molecule of albumen; two 
such molecules, with additional quantities of nitrogen, hydrogen, and 
oxygen, combined with a little sulphur, phosphorus, iron, or other 
mineral, make up, according to him, the constitution of the ordinary 
albuminoid. But his views are not considered altogether acceptable. 
The constituent chemical elements contained in cellulose are pre- 
cisely the same as those of starch, whose formula is ©,H,,O., but 
the arrangement of the atoms and molecules among themselves is 
undoubtedly very different, so that the physical and chemical proper- 
ties of starch and cellulose are very different. Starch, diastase, and 
cellulose may be considered as substances composed of molecules 
whose internal structures are respectively more and more complex; 
in the molecules of each of these substances the carbon, hydrogen, 
and oxygen are in the same proportions relative to each other both 
by number and by weight, but a molecule of diastase has twice and 
one of cellulose three times as many atoms as a molecule of starch. 
The composition of pure water is represented by the molecular 
formula H,O,, or by weight H 11, O 89, so that starch may be consid- 
ered as a compound of 6 atoms of carbon with 5 molecules of water. 
From the same point of view diastase would be compounded of 12 
atoms of carbon and 10 molecules of water, while cellulose would 
consist of 18 atoms of carbon and 15 molecules of water. These three 
substances are therefore called carbohydrates, as though carbon com- 
bined with water were to be considered as carbon combined with 
hydricacid. This term isnot to be confounded with the word * hydro- 
carbon,” which is applied to any compound of hydrogen and carbon, 
which, when combined with water or other molecules, forms a very 
different series of chemicals, such, for example, as C,H,, which is a 
hydrocarbon and when combined with 4 molecules of water or hydric 
oxide forms alcohol, making the latter, as it were, a hydrate of a 
hydrocarbon. , 
The approximate percentages by weight of the cellulose found in 
plants and vegetables dried at a temperature of 212° F. and the per- 
2667—05 M 2 
