ON A VARIETY OF CINCHONA BARK. 
181 
190 grs. This was exhausted with alcohol 35° Baume by 
boiling, and the alcoholic liquid, which had a light yellowish 
colour, was evaporated until crystals commenced to form, 
and set aside. Twenty grains of nearly colourless crystals 
were thus obtained, and the mother liquor, evaporated to 
dryness, afforded eight grains more of the same crystals con- 
taminated with a small amount of extractive, being 2.S per 
cent, altogether. The crystals were brilliant four-sided pri- 
sons with dihedral summits; had very little taste, but after a 
time gave an impression of bitterness; they are insoluble in 
water, soluble in alcohol, especially hot, and but slightly 
soluble in ether. They are strongly alkaline, and cold nitric 
and sulphuric acids dissolve without decomposing them. 
The sulphate, which crystallizes with great readiness, is solu- 
ble in water, has a bitter taste, and is precipitated by tannic 
acid. When dissolved in chlorine water, the addition of 
ammonia does not cause a green colour, indicative of quinia. 
The decoction of this bark is precipitated by sulphate of 
soda, though not so abundantly as calisaya ; it gives a dirty, 
greenish precipitate with persulphate of iron, a floculent 
white one with tincture of galls; tartar emetic instantly 
causes a white cloudiness, as also does oxalate of ammonia. 
When the filtered transparent infusion is dropped into a 
filtered solution of gelatin, the mixture becomes clouded, and, 
by standing, a very light floculent precipitate occurs. 
The above results show that this bark is destitute of qui- 
nia, that it contains no aricina, and that it contains nearly 
three per cent.'of cinchonia. The presence of this large per- 
centage of alkali, and of kinate of lime renders all the or- 
dinary chemical tests, as tincture of galls, sulphate of soda, 
etc., of little value, and in connection with the sensible cha- 
racters of the bark is well calculated to deceive, as in fact 
nearly all of them agree with the calisaya. The character 
of thespiculae noticed above, is the most striking difference, 
