THE VOLATILE PART OF PLANTS. 101 
Exp. 52.—Prepare a solution of vegetable casein from crushed peas, 
oats, almonds, or pea-nuts, by soaking them for some hours in warm 
water, and allowing the liquid to settle clear. Coagulate the casein by 
addition of an acid to the solution. It may be coagulated by rennet, 
and by salts of magnesia and lime, in the same manner as animal casein. 
The Chinese prepare a vegetable cheese by boiling peas 
to a pap, straining the liquor, adding gypsum until coagu- 
lation occurs, and treating the curd thus obtained in the 
same manner as practiced with milk-cheese, viz.: salt- 
ing, pressing, and keeping until the odor and taste of 
cheese are developed. It is cheaply sold in the streets of 
Canton under the name of. Zao-foo. Vegetable casein 
occurs in small quantity in oats, the potato, and many 
plants; and may be exhibited by adding a few drops of 
acetic acid to turnip juice, for instance, which has been 
freed from albumin by boiling and filtering. The casein 
from peas and leguminous seeds has been designated 
legumin, that of the oat has been named avenin. Almonds 
yield a caséin, which has been termed emulsin. As al- 
ready mentioned, casein (Ritthausen’s gluten-casein) exists 
in wheat-gluten, and in rye. Each of these sources yields 
a casein of somewhat peculiar characters; the causes of 
these differences are not yet ascertained, but probably lie 
in impurities, or result from mixture of other albuminoids. 
In crude wheat-gluten two other albuminoids exist, viz. : 
Gliadin, or vegetable glue, is very soluble in water and 
alcohol. It strongly resembles animal glue. 
Mucidin resembles gliadin, but is less soluble in strong 
alcohol, and is insoluble in water.. When moist, it is yel- 
lowish-white in color, has a silky luster, and slimy consist- 
ence. It exists also in rye grain. (Ritthausen, Jour. fur 
Prakt. Chem., 88, 141; and 99, 463.) 
Composition of the Albuminoids.—There are various 
reasons why the exact composition of the bodies just de- 
scribed is a subject of uncertainty. They are, in the first 
place, naturally mixed and associated with other matters 
