334- Dr. Stenhouse's Examination 



Myrobalans. — The name Myrobalans is applied to the 

 fruit of several East Indian trees, the species of which are, I 

 believe, not yet all accurately determined. That which I ex- 

 amined was the yellow kind, the fruit of the Jerminalia Che- 

 hula. The ripe fruit has a brownish-yellow colour, is pear- 

 shaped, and deeply wrinkled. It consists of a white pentan- 

 gular nut containing a small white oily kernel, and is covered 

 by a mucilaginous and very astringent husk, nearly two lines 

 in thickness. Each of the fruit weighs from 70 to 100 grains, 

 and of this 50 or 60 grains are husk. It is in the husk that 

 the whole of the astringent matter is contained, and it may 

 be easily separated from the nut by slightly pounding or 

 bruising the fruit. The powder of the husk is dark yellow, 

 and its taste is very sharp and astringent. The colour of its 

 aqueous infusion is deep yellow. With protosulphate of 

 iron it gives a deep bluish-black precipitate, which is rather 

 deficient in lustre. The dullness of the colour is owing to 

 the presence of impurities in the husk, for on purifying the 

 astringent matter by precipitating it with acetate of lead, 

 and then decomposing the lead compound with sulphuretted 

 hydrogen, the solution thus obtained gives as fine a colour as 

 can be procured from infusion of galls. With gelatine it gives 

 a very copious, slightly yellow precipitate, the quantity of 

 astringent matter contained in myrobalans being very consi- 

 derable. With tartar-emetic it also gives a copious brownish- 

 yellow precipitate. With protonitrate and protochloride of 

 iron, it gave bluish-black precipitates, which soon changed 

 to olive-black, and with acetate of iron, a fine purple-black 

 precipitate. When the decoction of myrobalans is evaporated 

 to dryness and distilled, it yields abundance of pyrogallic acid ; 

 this I found, however, to be derived, not from the decomposi- 

 tion of the tannin it contains, but from a quantity of ready- 

 formed gallic acid. Sulphuric acid occasions a very scanty 

 dark brown precipitate in the infusions of myrobalans, if at all 

 dilute, as the combination which this tannin forms with sul- 

 phuric acid is pretty soluble. From concentrated solutions, 

 the tannin is readily precipitated as a yellowish-brown tena- 

 cious mass. Having been collected on a cloth filter, and 

 freed as much as possible from adhering acid, it was dried 

 and distilled. It yielded no pyrogallic acid, and scarcely any 

 empyreumatic oil ; another portion of the same tannin, though 

 boiled in dilute sulphuric acid, was not converted into gallic 

 acid, but changed into a dark insoluble mass. 



Gallic acid may be readily obtained from myrobalans by 

 precipitating its decoction with a solution of glue, filtering 

 and evaporating to dryness. On treating the residue with 



