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oils but not by fixed oils. Tannic acid precipitates the aqueous 

 solution. When evaporated with liydrochloric acid and chlorate 

 of potash (or with chlorine- water), it leaves a remnant which 

 reddens the skin like alloxan and imparts to it a peculiar smell ; 

 the solution of the said residue, when mixed with alkalies and 

 salts of sub-oxyd of iron, acquires an indigo-blue colour, and 

 ammonia imparts to the residue a purple-red (murexid) colour 

 which does not turn violet by alkalies (distinction from uric acid). 

 [J. Williams gives the following method for prejDaring Caffein. 

 Mix finely-pulverised guarana with one-third hydrate of lime 

 and moisten with water. After an hour or two exsiccate at a 

 gentle heat, and exliaust with boiling benzol; filter and evajjorate, 

 but not to dryness. Treat with boiling water and digest on the 

 water-bath to the expvilsion of all traces of benzol. Filter 

 through wet j)aper, and evapoi'ate to a .small bulk, from which the 

 C. will separate after twenty-four hours pure and colouiiesS». — 

 According to H. M. Smith, Cafiein is contained to the amount 

 of 0"133% in the leaves of Ilex Cassine L. — Thomson avers that 

 in roasting coffee a great amount of Caffein is lost, which may be 

 regained by adapting to the burner a tube of about three feet length 

 wherein the vapours of C. are allowed to condense. One pound 

 of coffee yields on an average 75 grains of Caffein. C. is insoluble 

 in a concentrated solution of potassic carbonate. By treating an 

 infusion with subacetate of lead, concentrating and adding car- 

 bonate of potash, the C. is precipitated and may be obtained pure 

 by dissolving in alcohol and evaporating. By passing the gas, 

 evolved from chlorate of potash and hydrochloric acid, into an 

 aqueous solution of Caffein and evaporating to dryness on the 

 water-bath, a blood-red residue is obtained. One part Caffein in 

 1000 parts of water may thus be detected.] 



Cailceclrill. Bitter substance of the Cailcedra-bark (from 

 Khaya Senegalensis). Extract with hot water, evaporate to a 

 honey consistence, treat with alcohol of 33° Baume, add to the 

 solution sub -acetate of lead which precipitates a i-ed dyeing 

 matter, filter, remove from the filtrate the alcohol by distillation, 

 dissolve again in a little alcohol, remove the lead by sulphuret of 

 hydrogen, evaporate, shake the aqueovis liquid with chloroform 

 and bring the latter solution to dryness. A yellowish, gum- 

 resinous, brittle, very bitter substance, mollifies easily in hot 

 water, dissolves readily in alcohol, also in ether, chloroform, little 

 in water, of neutral reaction, yields a voluminous white precipi- 

 tate with ether. Consists of 64-9 C, 7-6 H and 27-5 O. 



Caleildulill. A substance, similar to vegetable mucilage, 

 in the flowers and leaves of Calendula officinalis. It is obtained 

 by treating the alcoholic extract, after it has been freed from a 

 green, waxlike substance, with water ; a voluminous, slimy 



