EXUDATIONS, JUICES, ETC. 
237 
flowing down the side of the tree where it hardens, or 
it is collected in special receptacles. 
Description. — In irregular, three-sided, more or less 
elongated pieces, one side being smooth and concave ; 
externally yellowish white; friable, somewhat waxy; 
internally whitish, porous and crystalline; odor sug- 
gestive of maple sugar; taste sweet, slightly bitter and 
acrid. 
Constituents. — The principal constituent is mannit 
(80 to 90 per cent.). Manna also contains a green fluo- 
rescent principle fraxin ; dextrose as high as 16 per 
cent.; mucilage; resin, and a small amount of inor- 
ganic substances. 
Allied Products. — The term “ manna ” is applied 
to a number of exudations obtained from different 
sources and of varying composition, none of which, 
however, appear to be supplied as a substitute for true 
manna, although they might be employed in a similar 
manner. 
Manna of inferior quality, known as “ sorts,” is 
obtained from incisions lower down on the stem, and 
consists of brownish yellow, more or less agglutinated 
tears, which are stick}^ and but slightly crystalline. 
TIiAGAC ANTHA (Tragacautli). 
A gummy exudation from the stem of Astragalus 
gmmijeru and other species of Astragalus (Fam. Legu- 
minosie), shrubs indigenous to Western Asia. Traga- 
canth exudes naturally, or it is obtained by making 
transverse incisions in the stem, the gum being col- 
lected after it dries. The principal points of export 
are Smyrna and various ports along the Persian Gulf ; 
that obtained from the latter is known as Persian or 
Syrian Tragacanth and is preferred. 
