44 
TESTS FOR CINCHONA BARKS. 
of a darker yellow. Huamalies bark, exhausted in the same man- 
ner, furnishes a dark yellow infusion of a less aromatic odor than 
the yellow bark, and with ammonia an ochreous precipitate like 
the brown Huanuko bark ; but the filtered ammonical liquid is not 
yellowish-brown, but red, almost like the infusion of C. regia. 
The false barks furnish with pure water and with water to which 
a little sulphuric acid has been added, much darker-colored infu- 
sions than the genuine barks ; they possess a more astringent 
taste, and furnish no alkaloid when mixed with ammonia until 
they have an alkaline reaction- 
If it be desired to ascertain the amount of alkaloid more accu- 
rately than is possible according to the above method, the acid ex 
tracts must be concentrated as much as possible by evaporation ; 
moreover, the alkaline liquids filtered from the precipitated alka- 
loids should be evaporated to dryness in order to remove from them 
the remainder of the quinine or cinchotine. 
The alkaloids precipitated from the acid infusions of the barks 
by ammonia or carbonate of soda are, in every case, combinations 
of them with a humus-like cinchona coloring substance, which in 
the C. regia is a different one from that contained in the brown 
kinds of bark, and is present in variable quantity. This coloring 
matter may be very easily separated from the alkaloid by acetate 
of lead. 
It may be assumed that 1 oz. of yellow bark, exhausted with 
12 oz. of water and from J to 1 scruple of dilute sulphuric acid, 
will furnish, on precipitation by ammonia, not less than 10 grs. or 
2 per cent, of the weight of the bark of colored quinine. 
The brown or Huanuko bark gives, on being treated in the same 
manner, only from 8 to 9 grs. of colored alkaloid, and frequently 
less. Besides cinchonine, it contains another alkaloid, which is 
soluble both in ether and in water containing soda, and which is 
not quinine, but most probably cinchotine. 
1 oz. of the Huamalies, or rusty bark, furnished 7*5 grs., or 
1*54 per cent, of colored alkaloid ; it is therefore one of the richer 
kinds, and most probably more active. However, no quinine could 
be detected in it ; for the portion which was pretty soluble in 
water and ether, tm being dissolved in chlorine-water, was not ren- 
dered green by ammonia ; it may therefore be assumed as highly 
probable, that the Huamalies, like the Huanuko bark, contains cin- 
chotine besides cinchonine. 
