THE VOLATILE PART OF PLANTS. 1 01 



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 Tao-foo. Vegetable casein 

 I 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 

 yieW~rr~casein, 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. : 



Giiadin, 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, far 

 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 matter 



