ELASTIC A 285 



305 c. EUPHORBIA PILULIFERA, N.F. Linn6. A common herb along the road- 

 sides in Australia, where it enjoys a great reputation for the prompt and 

 complete relief it gives in asthma and pectoral complaints generally. Dose: 

 15 to 60 gr. (i to 4 Gm.). 



306. EUPHORBIUM. EUPHORBIUM. A gum-resin exuding from one or more 

 undetermined species of Euphorbia, ascribed to some leafless, cactus-like 

 plants of Egypt, Arabia, and the East Indies. It occurs in dull brownish- 

 yellow or reddish, rounded pieces of the size of a pea or larger, often pierced 

 with, or inclosing, the spines around which it has hardened on the stem of 

 the plant; almost inodorous, the powder sternutatory; taste mild at first, 

 but afterward intensely acrid and burning. Only used externally, mostly in 

 veterinary practice as a vesicant. 



307. ALVELOZ MILK. The milky juice of a Brazilian plant, Euphor'bia hete- 

 rodox'a Miiller. It has an action resembling that of papain, and is used in 

 eating out cancerous and other ulcers. 



308. MERCURIALIS ANNUA Linn6. MERCURY WEED. A European herb, em- 

 ployed from the most ancient times as a purgative and emmenagogue. 



309. ELASTIC A. INDIA-RUBBER (U.S.P. VIII) 



CAOUTCHOUC 



The prepared milk-juice of He'vea Braziliensis Mueller and other species, known 

 in commerce as Para rubber. Large trees containing a milky juice which, 

 on hardening, forms india-rubber. Ficus elastica, producing the greatest 

 quantity, has its seeds germinate in the forks of the tree, giving off aerial 

 roots which descend to the ground and form a great many trunks. 



HABITAT. South America and India, the finest quality coming from Brazil. 



DESCRIPTION. Large, flat pieces, or molded into various shapes balls, hollow, 

 bottle-shaped pieces, etc. When the juice first hardens it is yellowish-brown 

 externally and yellowish-white within, but in the processes of molding and 

 drying it acquires a smoky, blackish appearance; very elastic; odor peculiar. 

 Insoluble in water and alcohol, but soluble in chloroform, carbon bisulphide, 

 and benzin. The common adulterants are the earbonates of zinc and lead; 

 when pure or nearly pure, india-rubber should float in water. 



CONSTITUENTS. The elastic principle has been termed caoutchoucin ; it, or a similar 

 principle, is contained in a great number of milky-juiced plants. 



USES. On account of its insolubility it has no therapeutic application, but is 

 extensively used in the arts. Employed in some of the pharmaceutical 

 plasters, e.g., Emp. Elasticum. U.S. IX. 



310. LACCA. LAC. GUM-LAC. A resinous exudation from punctures, made 

 by insects, in the bark of several East Indian trees, and also in plants grow- 

 ing in Arizona and other Western States. The twigs, with their deep red- 

 dish-brown incrustations, are called stick-lac. Seed-lac consists of the 

 small, irregular fragments broken off from the twigs. Lump-lac is made 

 bytmelting the stick-lac, and, after it has hardened, breaking the brown, 

 translucent mass into lumps. Shell-lac or gum-shellac, the most common 

 form, is prepared by spreading the melted lac out in thin layers, which, 

 on drying, form thin, brittle sheets, glossy, more or less transparent, vary- 

 ing from amber to dark brown in color; in packing, these sheets are broken 

 into fragments, in which form shellac is commonly met with in market; 

 odorless and tasteless. Lac contains several resins, laccin (a peculiar prin- 

 ciple insoluble in alcohol), and a coloring matter varying in quantity in 

 the different forms; this coloring matter, "lac dye," is equal to cochineal 

 dyes: it is soluble in water, being obtained from the washings in making 

 the different forms of lac. Lac is not used medicinally, but is extensively 

 employed in the arts for making varnishes and sealing-wax. 



