coiistitiient Parts of astnngent VegetaUcs. 217 



cimens of that substance must difler ia some measure in 

 their composition, even in their pure states ; and, for the 

 pui poses of commerce, tliey are often adulterated to a con- 

 siderable extent with sand and earthy matter *. 



In attempting to estimate the composition of the purest 

 cateclm, I selected pieces from different specimens, with 

 which I was supplied by the president, and reduced them 

 together into powder j mixing, however, only those pieces 

 which were from catechu of the same kind. 



Two hundred grains of the powder, procured in this way 

 from the catechu of Bombay, afforded by analysis 



Tannin - - - - ' 109 grs. 



Peculiar extractive matter - - gs 



Mucilage - - _ _ 13 



Residual matter, chiefly sand and calcareous 

 earth - - . - 10 



The powder of the Bengal catechu gave, by similar me- 

 thods of analysis, in 200 grains, 



Tannm - ^ . . . ^^ ^^ 



recuhar extractive matter - - 73 



INIucilage - - - _ _ 16 



Residual matter; sand, ^^ith a small quan- 

 tity or calcareous and aluminous earths, 14 

 In examining those parts of the catechu from Bengal 

 which were differently coloured, I found the largest pro- 

 portion of tannin in the darkest part of the substance ; and 

 most extractive matter in the lightest part. It is probable 

 that the inequality of composition in this catechu is owino- 

 to its being evaporated and formed without nuich agitation'- 

 in consequence of which the constituent parts of it that arc 

 least soluble, being first. precipitated, appear in some mea- 

 sure distinct from the more soluble parts, w hich assume 

 the solid form at a later period of the process. 



Prom the observations of Mr. Korr f it would appear that 

 the pale catechu is that most sought after in India j and it 

 is evidently that which contains" most extractive matter. 

 The extractive matter seems to be the substance that gives 

 to the catechu the peculiar sweetness of taste which follows 

 the impression of astringency ; and it is probably this 

 sweetness of taste which renders it so agreeable to the Hin- 

 doos, for the purpose of chewing with the betlc-nut. 

 [To be continued.] 



* One Epecimcn that I examined of tbe terra japonica of commerce, 

 fnniished, hy incineration, one-fifth of sand and earthv m.ittcr; and au^ 

 other specimen nearly one-sixth. 



i ^ltdlcal Ouctrvation*. vol. v. p. J5;, 



' .\XXMf. Of 



