217 



of water, dry the remnant, until the wliole of the petroleum is 

 driven away, dissolve in alcohol and throw down the Th. either 

 by digesting with hydrate of lime or better by alcoholic acetate of 

 lead. The green flocks obtained ai'e, after filtering and boiling 

 with ether, separated from the lead-oxyd by means of acetic acid. 

 — Brittle, green mass, insoluble in water, scarcely soluble in hydro- 

 chloric acid, soluble in strong alcohol, ether, and oils. 



Tliebuill = Css H21 NOe. In opium, to all apjiearance in Papaver 

 Rlioeas too, associated with rhoeadin. By heating, as indicated 

 under morphin, the aqueous extract of opium with milk of lime, 

 the morphin I'emains dissolved, while the Thebain is left in the 

 lime-sediment. Wash the latter, dry, boil with alcohol, evaporate 

 the extract and treat the remaining brown, granular mass with 

 ether, which dissolves the Thebain, and leaves it on evaporating 

 as a brown, crystalline mass. Purify by dissolving in acid, precipit- 

 ating with ammonia and recrystallising in alcohol or in ether. — 

 White, silvery, quadratic leaflets, also needles, grains and cauli- 

 flower-shaped masses, very electric on rubbing, of a more acrid and 

 styptic than bitter taste, of alkaline reaction; fuses at 150° with- 

 out loss of weight, and decomposes in a higher temperature; 

 dissolves not, or slightly in water; readily in alcohol, ether, 

 diluted acids, becomes deep-red with concentrated sulphuric acid, 

 and dissolves with yellow colour; becomes blood-i-ed with sul- 

 phiu'ic acid, containing nitric acid. Its salts are not crystallisable 

 from water, but are so from alcohol and from ether. 



Tlieill = Caffein. 



Theobroillill = Cu Hs N4 O4. Alkaloid of the seeds of Theo- 

 broma Cacao. Precipitate the aqueous extract of the prej)ared 

 seeds with acetate of lead, filter, free the filtrate from lead by 

 sulphuret of hydrogen, concentrate to honey-consistence, boil with 

 alcohol, evaporate the tincture and recrystallise what has formed. 

 — White, crystalline powdei", inodorous, of a bitter taste, slightly 

 similar to cacao, sublimates at 290° to 295°, fusing at the same 

 time; dissolves in 1600 parts of cold and in 55 parts boiling 

 water, in 1460 parts cold and 47 jmrts boiling alcohol of 80 °/q, 

 in 17,000 parts cold and in 600 parts boiling ether; all these 

 solutions having a neutral reaction ; dissolves readily in alkalies 

 and in diluted acids. The very diluted solution in nitric acid, 

 yields with nitrate of silver a silvery- white, crystalline deposit; 

 the ammoniacal solution yields with nitrate of silver a jelly-like 

 deposit soluble in warm liquor of ammonia. On boiling this 

 solution ammonia is evolved and a colourless, granular, crystalline 

 ■deposit of Tlieobromin-silver = C14 H7 Ag N4 O4 is obtained. 



Tlllljili:=C4o H22 O24. Dissolve the deposit, obtained in the 

 following paragraph by means of acetate of lead, in diluted acetic 



