60 CINCHONA BARKS. 
The presence of gum, as also of sugar, has not been more 
accurately proved in the Cinchona barks. __ 
The phlobaphen which, in 1844, was precipitated by Stahelin and 
Hofstetter from an alcoholic tincture of the yellow Cinchona by 
means of sulphuric acid, as also the /ignomm, prepared in 1856 by 
Reichel, are quite as insufficiently investigated as the corresponding 
substances occurring in oak bark.* Reichel’s lignoin may be 
obtained when Cinchona, which has been exhausted by ether, 
alcohol and water, is extracted with caustic lye, and is then pre- 
cipitated, on the addition of an acid, as a dark brown substance, 
which, in its dry state, may amount to from 2 to 1g per cent. of the 
bark. 
The Cinchona barks contain tannin, which affords with ferric 
salts a bright green, or, when other coloring principles of the 
barks co-operate, a darker brownish-green precipitate. This czzcho- 
tannic acid also produces a precipitate in a solution of gelatin. 
Reichardt found in Cinchona (China) flava fibrosa 1 per cent., in 
flat Calisaya 3%, and in quill Calisaya, 2 per cent. of tannic acid ; 
Reichel, ‘in flava fibrosa (the Tunita bark mentioned on page 18), 
3.8 per cent. When separated from the lead salt, the cincho-tannic 
acid represents, according to Schwarz (1851), a bright yellowish,very 
hygroscopic mass, of an acidulous, and at the same time astringent, 
but not bitter, taste. Upon heating the cincho-tannic acid at but 
100° C, (212° F.), or by the evaporation of its aqueous solution, 
especially after the addition of acids or alkalies, red products are 
formed—in the latter case with absorption of oxygen. By precipi- 
tating the red-brown ammoniacal extract of Cinchona with an acid, 
the cznchona-red is obtained, which, when dried, is a dark red or 
brownish-red, odorless and tasteless mass, insoluble in ether, water, 
and dilute acids, but soluble in alcohol. The ammoniacal solution 
of cinchona-red affords, with alum, a red lake. With a fraudulent 
purpose, the attempt has already been made to impart to yellow 
Cinchona barks the appearance of the more expensive red varie- 
ties by moistening them with ammonia. The aqueous extract of a 
bark which has been treated in this way is remarkably colored, and 
affords, with Nessler’s reagent? a reddish-brown, not a white pre- 
cipitate; chloride of platinum also produces an abundant precipi- 
tate, while the Cinchona barks, as previously intimated, p. 59, can 
furnish but very little ammonio-platinic chloride. : 
1 Flickiger, Pharmakognosiz, 1882, p.475. 
2 Fliickiger, Pharm. Chemie.,1878, p. 38; Kubel and Tiemann, An/ettung zur Unter- 
suchung von Wasser, 1874, p. 142; Hoffman and Power's Examination of Medicinal 
Chemicals, p. 40. oe a eee 
3 Thomas et Guignard, Répertoire de Pharmacie, 1882, p. 337- 
