236 
PHARMACOGNOSY. 
Adulterants. — Gamboge is sometimes adulterated 
with vegetable fragments, inorganic substances, as 
sand, etc., and wheat or rice flour, which it may contain 
to the extent of nearly 50 per cent. 
LACTUCARIUM. 
The dried milk-juice of Laduca virosa and other 
species of Laduca (Fam. Corapositse), biennial herbs 
indigenous to Central and Southern Europe and culti- 
vated in France, England and Germany, certain species 
being more or less naturalized in the United States. 
Lactucarium is obtained by cutting off the tops of the 
stems ; and wdien the latex which exudes is partially 
hardened, it is collected and dried in hemispherical 
earthen cups until it can be cut into pieces, usually 
four in number, these being further dried. 
Description. — In irregular angular pieces or quad- 
rangular sections, one surface of which is convex ; 
externally dull reddish or grayish brown ; fracture 
tough, waxy ; internally light brown or yellowish, some- 
what porous ; odor distinct, opium-like ; taste bitter. 
Lactucarium is partly soluble in alcohol and in ether, 
and should not give a reaction for starch. 
Constituents. — Three bitter principles: lactucin, lac- 
tucopicrin and lactucic acid, the latter being crystalline; 
also a colorless, odorless and tasteless crystalline prin- 
ciple lactucerin ; volatile oil; mannit; organic acids, 
as citric, malic and oxalic, and ash 7 to 10 per cent. 
MAMA. 
The dried saccharine exudation from the stems of 
Fraxinus Ornus (Fam. Oleaceae), a small tree indigenous 
to Southern Europe, where it is also cultivated, particu- 
larly in Sicily. Manna is obtained by making trans- 
verse or oblique incisions in the bark, the exudation 
