666 BOTANY AND PHARMACOGNOSY. 



Jaffarabad Aloes is a vitreous variety obtained from the 

 East Indies and is exported from Bombay. It occurs in circular, 

 flattened cakes, of a deep black color externally, and with a black, 

 glossy, slightly porous or somewhat laminated fracture. It yields 

 about 20 per cent, of aloin, which is apparently chiefly isobarba- 

 loin, and gives a deep crimson color with nitric acid. 



CATECHU. — An extract prepared from the heartwood of 

 Acacia Catechu (Fam. Leguminosse), a tree (p. 294) indigenous 

 to India and Burmah, and from the leaves and twigs of Uncaria 

 (Oicrouparia) Gambir (Fam. Rubiacese), a climbing shrub (p. 

 381) indigenous to Malacca, Java and Sumatra and mostly culti- 

 vated near Singapore, the former being known as " black catechu " 

 or " cutch," and the latter as " pale catechu," " gambir," or " terra 

 japonica." These extracts are prepared by boiling the parts of 

 the trees and shrubs yielding them with water, evaporating the 

 strained liquid to a syrupy consistence and allowing it to harden. 



Black Catechu. — In irregular masses, with fragments of 

 leaves or mats upon the outside, dark brown, somewhat shiny; 

 brittle, more or less porous internally; odor slight; taste astrin- 

 gent and sweetish. 



Catechu is somewhat soluble in cold water, the undissolved 

 portion containing acicular crystals ; almost entirely soluble in 

 boiling water, the solution giving an acid reaction; not less than 

 70 per cent, should be soluble in 90 per cent, alcohol. Few or 

 no starch grains or vegetable tissues should be present, and the 

 ash should not be more than 5 per cent. 



Gambir or Pale Catechu. — Usually in more or less porous 

 irregular cubes, about 25 mm. in diameter; externally dull red- 

 dish-brown ; friable ; internally paler, consisting chiefly of micro- 

 scopic crystals when examined in a drop of oil ; odor slight ; 

 taste bitter and very astringent. 



Constituents. — Catechutannic acid, 25 (black catechu) or 

 22 to 50 per cent, (pale catechu), giving a green color and pre- 

 cipitate with ferric chloride and in other respects resembling the 

 tannin in oak bark, kino ■ and krameria ; a substance somewhat 

 resembling gallic acid, catechin, which crystallizes in silky 

 needles; catechu-red; quercetin (p. 544), and ash about 3 per 

 cent. Pale catechu contains in addition a fluorescent principle. 



