160 .Tjm^ms. 



billai correspond exactiy to gallof annic atid, and all that has. been 

 said of the latter is equally true bf the former. They are always 

 accompanied by gallic acid in the materials that yield them. 



Some of these also contain the . so-called ellago-tannic. acid, 

 which is foiidd in notable- quantities in myrobalaiis, 4ivi-divi and. 

 bablali fruits.' 



This ellago-tannio acid, which, as far as Loewe's experiments 

 show, is not a glucoside, dilfers from gallotannie acid in yielding 

 ellagicin the place of gallic acid, a change that can be brduglit 

 about by W3,ter alope at a teftiperature of 108 to 1 10°^ EUagic 

 aoid cap be obtained in sulphur-yelJow crystals, whioh are almost 

 insoluble in boiUng water or in ether, and sparingly soluble iit 

 aloohoL Nouvithstanding, however, its slight solubiUty in atbcr, 

 .small quantities can be removed from aqueous solution by shirk- 

 ing wiDh that Jiqiiid, FerriO chloride produces first a green, thotr 

 an inky colouration, it is soluble in potash, and is jirecipitated 

 by acetate of lead froni an alooholic solution in the form of lead- 

 salt, containing 03 per cent, of oxide, The dry -substance liseated 

 with zinc dust yields the hydrocarbon eUagene (GjjHjj), which 

 cannot be combined with picric acid. 



Whether elkgo-tannic. acid, has been prepared ifl a state of 

 purity, and whether. it is idenlioal with punioo laetnio aeia,"are 

 queati'odjs which we may for the present Icare but of consLdersr 

 tion. According to Rembpld, the latter also, yields elJagie acid) 

 Special methods for the estimation o.£ these two substances havie 

 liot as yet been published. 



For nymphsea-tannic acid see^g 161. 



Gallotannic tind gallic acids also occur in tea, accompanied by 

 quercetin (possibly present in sumach also, § 152), and by the so- 

 called boheic acid.* The latter is not thrown down when acetate 

 of lead is added to a hot infusion of tea, but is precipitated on 



Chem. xii. 128, 1873 (Journ. Chem. Soo. zxvi. 748); liv, 46 (tftttnin of 

 knoppem-galls). 



^ Compare Godeffroy, Zeitsotr. d. Oeeterr. Apoth.-Ver. 182, ,1879 (Year-book 

 Pharm. 215, 1879). 



^ C<>mpare Giintber, loc. cit. Also my obaei'TationE in the Jahresbericht f. 

 Pharm. 192, 1875 ; and Lo'ewe, Zeitsohr. f. anal. Ohem. xii. 128 ; xiv. 35, ii. 



' Anna!, d. Chem. uud Pharm.' oxiiii. 285, 1867. I may observe that in the 

 pomegranate bark also the substance yielding ellagic acid is accompanied by 

 faUotannic acid, and that Kembold obtained' sugar by the decompusitioti of 

 the former. 



* Compare IQasiwetz, Annal. d. Chem. nnd Fharm. cxlii. 233. 



