CRUDE DRUGS. 649 



and Malaya, as G. colliiia, of New Caledonia; Vismia laccifcra, of 

 Brazil ; Clitsia rosea, of the West Indies and South America, and 

 Cliisia macrocarpa, of Guiana. Gamboge of a poor quality is 

 obtained from Arasina Gurgi, of India. 



Adulterants. Gamboge is sometimes adulterated with veg- 

 etable 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 Lactnca virosa 

 and other species of Lactnca (Fam. CdniposittX ) , biennial herbs 

 (p. 392) 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 when the latex 

 which exudes is partially hardened, it is collected and dried in 

 hemispherical earthen cups until it can be cut into pieces, which 

 are usually four in number, these being further dried. 



Description. In irregular, angular pieces or quadrangular 

 sections, one surface of which is convex ; externally dull reddish- 

 or grayish-brown ; fracture tough, waxy ; internally light brown or 

 yellowish, somewhat porous ; odor distinct, opium-like ; taste bitter. 



Lactucarium is partly soluble in alcohol and in ether, and 

 about 50 per cent, is soluble in water, but the solution should not 

 give a reaction for starch. 



Constituents. -Three bitter principles : lactucin. which 

 occurs in white rhombic prisms that are sparingly soluble in 

 water; lactucopicrin, a brown, amorphous, very bitter principle 

 which is readily soluble in water and alcohol ; and lactucic acid, 

 a yellow, very bitter substance crystallizing with difficulty and 

 colored red by alkalies. The drug also contains about 50 per 

 cent, of a colorless, odorless and tasteless crystalline principle, 

 lactucerin (lactucon) ; a- and ^-lactucerol in the form of acetates; 

 volatile oil ; mannitol ; organic acids, as citric, malic and oxalic, 

 and 7 to 10 per cent, of ash. 



A mydriatic alkaloid has been found in Lactnca virosa and in 

 L. miiraJis. 



MANNA. The dried, saccharine exudation from the stems 

 of Fraxinns Ornus (Fam. Oleacege), a small tree (p. 360) indig- 

 enous to Southern Europe, where it is also cultivated, particularly 



