78 



CHEMICAL CONSTITUTION OF VEGETABLES. 



many different seeds. Legumine, which plays an important part in 

 the nutrition of animals, is obtained by digesting a quantity of pea 

 or bean meal, 3r crushed peas or beans in tepid water for two or 

 three hours ; the pulp is then pounded in a mortar, and afterwards 

 mixed with its own weight of cold water ; after one hour's macera- 

 tion it is pressed through a cloth. On standing, the liquid throws 

 down some fecula. Filtration is employed to have the liquor per- 

 fectly clear; upon which a quantity of acetic acid diluted with from 

 eight to ten times its weight of water is gradually added, when a 

 snowy flocculent precipitate of legumine falls. This is collected in 

 a filter and washed with water ; the legumine is then treated with 

 alcohol, dried, and pulverized, preparatory to digestion in ether, in 

 order to free it from fatty matters. 



Legumine thus prepared has a pearly or lustrous appearance. It 

 is insoluble in alcohol and ether. Cold water dissolves it in large 

 quantity. On boiling the watery solution, legumine is coagulated 

 and falls in flocculi analogous to those formed by albumen under the 

 same circumstances. Weak hydrochloric acid throws down legu- 

 mine from its watery solution like the acetic acid ; the concentrated 

 acid, again, dissolves it, acquiring a violet tint, a character which 

 also belongs to albumen ; but that legumine is actually distinct from 

 albumen is proved by the circumstance of its being precipitated by 

 phosphoric acid with three atoms of water, which albumen is not. 

 The alkalies dissolve legumine at common temperatures. 



COMPOSITION OF LEGUMINE, OBTAINED FROM DIFFERENT SEEDS.* 



These same azotized compounds, or substances dilfering but little 

 from them, are very probably those that are now recognised as dis- 

 tributed through the whole body of every vegetable. M. Payen, 

 after having ascertained the presence of these substances in the 

 radicles and spongioles, proved it in nearly all the organs. The 

 examination was extended to a great number of species of different 

 families. The ascending sap of a fig-tree, {Jicus carica,) that of the 

 lime-tree, of the black poplar, of the vine, have all yielded ammoniacal 

 vapors under the influence of fire; so also do the buds, the young 

 leaves, the stigmas, the anthers, &c.t Thus, according to M. Fayen, 

 the nutritious juices which ascend from the extremities of the radi- 

 cles to the terminal points of the leaves, carry an azotized principle 



• Damas ct Cahours, Annnles de Chimie et de Physique, t. vl„ p. 423, 3e «*ri«. 

 t Payen, M^molre sur les d^veloppemens des v^g^taux, p. 3G. 



