CRUDE DRUGS. 441 



Description. — A white, sgft tufted mass, consisting of some- 

 what flattened, twisted and spirally striate, i -celled, non-glandular 

 hairs, from 2.5 to 4.5 cm. long ; inodorous and tasteless. 



Absorbent cotton is soluble in ammoniacal solution of cupric 

 oxide, yields less than i per cent, of ash, and on treating it with 

 water the solution should have a neutral reaction and not give any 

 reaction with ammonium carbonate, barium chloride, mercuric 

 chloride or silver nitrate. 



Adulterants. — Various substances may be added to absorbent 

 cotton to increase the rate of absorption of water, as chlorides of 

 calcium, magnesium and zinc, glycerin and glucose; as loading 

 materials, barium and calcium salts, and clay are added to inferior 

 grades of the article. 



The hairs from irnmature seeds are known as " dead cotton " 

 and are distinguished by having very thin walls, a thin outer 

 layer of cutin, but lack the essential properties for technical uses. 



GUARANA. — A dried paste consisting of the crushed seeds 

 of Paullinia Cupana (Fam. Sapindaceae), a climbing shrub native 

 of Brazil and Uruguay. The commercial product is obtained from 

 cultivated plants. The ripe seeds are deprived of the appendage 

 or aril, crushed, made into a doughy mass with water, sometimes 

 tapioca being added to increase the adhesiveness, molded into 

 forms and dried at a gentle heat. During the drying the mass 

 undergoes a kind of curing. Considerable skill is required in 

 supervising the operation, which is performed by special work- 

 men. In addition to its use in medicine, Guarana is used in the 

 preparation of a beverage which is used like tea and coffee by the 

 people of Brazil (p. 324). 



Description. — Cylindrical sticks, 15 to 30 cm. long, 35 to 50 

 mm. in diameter; externally blackish-brown, surface marked by 

 depressions, but otherwise smooth; hard, heavy and brittle, the 

 fracture being uneven; internally hght brown to reddish-brown, 

 somewhat variegated from the fragments of contused seeds ; odor 

 slight; taste astringent, bitter. 



Constituents. — Caffeine 2.5 to 5 per cent. ; tannin (catechu- 

 tannic acid) about 25 per cent. ; ash about 2 per cent. Guarana 

 .also contains considerable starch, a small amount of catechin, a 

 volatile oil, an acrid, green fixed oil, and saponin. (Also see Cola.) 



