VEGETABLE FIBRINE. 45 



constituents. Animals cannot be fed on matters desti- 

 tute of these nitrogenized constituents. 



These important products of vegetation are especially 

 abundant in the seeds of the different kinds of grain, 

 and of pease, beans, and lentils ; in the roots and the 

 juices of what are commonly called vegetables. They 

 exist, however, in all plants, without exception, and in 

 every part of plants in larger or smaller quantity. 



These nitrogenized forms of nutriment in the vegeta- 

 ble kingdom may be reduced to three substances, which 

 are easily distinguished by their external characters. 

 Two of them are soluble in water, the third is insoluble. 



When the newly-expressed juices of vegetables are 

 allowed to stand, a separation takes place in a few min- 

 utes. A gelatinous precipitate, commonly of a green 

 tinge, is deposited, and this, when' acted on by liquids 

 which remove the coloring matter, leaves a grayish 

 white substance, well known to druggists as the deposit 

 from vegetable juices. This is one of the nitrogenized 

 compounds which serves for the nutrition of animals, 

 and has been named vegetable fibrine. The juice of 

 grapes is especially rich in this constituent, but it is 

 most abundant in the seeds of wheat, and of the cerealia 

 generally. It may be obtained from wheat flour by a 

 mechanical operation, and in a state of tolerable purity ; 

 it is then called gluten, but the glutinous property be- 

 longs, not to vegetable fibrine, but to a foreign sub- 

 stance, present in small quantity, which is not found in 

 the other cerealia. 



The method by which it is obtained sufficiently proves 



