CINCHONA.

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of emetic tartar, which causes a dirty white precipitate (the nature of,c h has been before discussed, p. 993).

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™°XBTzr .—Various alcaloimetrical processes, applicable to thekind s - na k ai ’k s > have been recommended. They are essentially of twotat e tlj SOlne consist in the use of certain reagents or tests which precipi-ce ( ,J. e a ^aloids from an infusion of the bark,—others are processes for

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as

^traction of the alkaloids, which are obtained either in the free states alts (disulphates).

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)jg CESSE . s BY tests.— a. Tannic acid is a very delicate test of the Cinchona alka-( j CS > w hich it precipitates from their solutions, in the form of tannates. On this^ e pends the value of infusion or tincture of nutgalls, employed as a test of thejj°»cliiess of bark by Vauquelin (op. supra cit.), by Berzelius (op. supra cit.) and■ Henry (Journ. de Pharm. xx. 429).

Chloride of Platinum . —Duflos’s quinometrical method (Pharm. Centr-ff att far 1831, S. 537) is founded on the property of the cinchona alkalies tow*tli [neutral] chloride of platinum double salts (platinum-chi >rides of thew a ‘°tds) which are insoluble in alcohol, and very difficultly soluble in cold1 ,^ ne » ra ' n these s <d ts dried in the air contains about J grain of the

0 j. Y ' Bichloride of Mercury. —As bichloride of mercury forms with hydrochloratcs1 quinia and cinchonia, double salts (mercury-bichlorides of the alkaloids') whichit) 6 ° n ^ s hghtly soluble in water and in alcohol, it may perhaps be applicable,,, some cases, as an alcaloimetrical test.

^Traction of the Cinchona Alkalies. —The methods of extracting cinchoniar .. *l u inia from bark for alkaloimetrical purposes are various. They may beerr ed to under four divisions:—

P “• By Alcohol. —Some chemists begin by preparing an alcoholic tincture oft j a| k, without using in the first instance either acid or mineral alkali. This isT'u adopted by Pelletier and Caventou (Joum. de Pharm. vii. 52), by

j, '°,y (Ibid. xiii. 530), and bv Bonnet (Pharm. Central-Blatt fur 1832, S. 900).r ” m this tincture the alkaloids may be extracted by various processes.

”• By Acidulated Liquids, without the previous me of alkaline solutions. —InTZ a (kaloimetrical processes the bark is digested in spirit, acidulated with’[•phuric or hydrochloric acid: as in those of Henry fils (Journ. de Pharm. xvi.

)> and Stoltze (Pharm. Central-Blatt fur 1832, S. 890). In others acidu-ted water is used, as in the methods of Von Santen (Bergen , Monogr. 343),enry ant ] p]; sson (J IJUrn , J e Pharm. xiii. 270), and Winkler (Pharm. Central-Blatt fir 1835, S. 509).

hiTl ^ -Acidulated Liquors, after the use of alkaline solutions. — Scharlau’sred CP harm. Central-Blatt fur 1832, S. 487) is founded on the property of

c 'nchonic and cinchona-tannin (with both of which the cinchona-alkaloidsffi 6 k° m kined) to dissolve in caustic alkalies, and thereby to be extracted fromr e 6 BarB: the cinchonia and quinia which are left behind may be subsequently^ttioved by an acidulated liquor. Badollier (Dumas, Traite de Chem. v. 745)Iti° f m P lo y e d caustic potash ; Stoltze (Ibid. 746) a mixture of lime and water.

, die process of the Edinburgh pharmacopoeia for the manufacture of disul-* a ' e of quinia an alkaline carbonate (carbonate of soda) is used.

• By Water. —The Edinburgh pharmacopoeia gives the following direc-0 p.?| or ascertaining the good quality of yellow bark. “ A filtered decoction00 grains in two fluid ounces of distilled water gives, with a fluid ounce ofiti 1C . en * rat . e d solution of carbonate of soda, a precipitate, which, when heatedea '1 becomes a fused mass, weighing when cold 2 grains or more, and

dy soluble in solution of oxalic acid.” In this process the native salts ofca | IIUl extra cted by the boiling water are decomposed by carbonate of soda, andqj, °nate of quinia precipitated. By heat the quinia fuses.

Pl°yed i a ^ ove T'inometrical processes I give the perference to that cm-'h'iiiia Edinburgh College in the manufacture of disulphate of

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separation of quinia and cinchonia, in order to estimate the quan-