MATERIA MEDICA AND THERAPEUTICS.
On Adulteration of Sulphate of Qicinine. By Dr. Moll.—The ex-
cessive price of the true cinchona, the calisaya of Bolivia, has led to the
substitution of many inferior kinds, chiefly remarkable for their con-
taining large proportions of quinidine. In consequence of their lower
price they have obtained admission to the quinine manufactories in
large quantities, and much of the sulphate now produced is depreciated
by the addition of quinidine. This substance differs from the sulphate
of epiinine by its greater specific gravity and less flocculent crystalliza-
tion, and it is much more soluble than it is in water and alcohol. The
addition of both cinchonine and quinidine may be detected by means of
ether ; for while cinchonine is almost insoluble in this substance, quini-
dine is so in a far less degree than is quinine, inasmuch as sixty drops
of ether and twenty of ammonia will dissolve ten grains of quinine and
only one grain of quinidine. On the addition of these quantities of sul-
phuric ether and liq. ammonia, to ten grains of quinine, with ten drops
of dilute sulphuric acid, and fifteen of water, all will remain dissolved,
unless cinchonine, or more than ten per cent, of quinidine be present,
the mechanical impurities only appearing at the surface. If 10 per
cent, of quinidine be present in the ethereal solution, it will soon crys-
tallize on the surface of the ether. Traces of this substance can be yet
more certainly discovered if ether saturated with quinidine be employed,
when all that exists in the suspected salt will remain insoluble. If the
powder contain cinchonine or more than 10 per cent, quinidine, it will
remain undissolved at the line of demarcation of the two fluids. If it
be quinidine, it is soluble in additional ether, which cinchonine is not.
To establish the purity of quinine, we must also assure ourselves of
the absence of inorganic substances, by calcination in platina, or by a
solution of the salt in alcohol. Sulphate and carbonate of lime, mag-
nesia, &c., remain undissolved, while boracic acid, though soluble, be-
trays itself by its blue flame on conflagration. The absence of organic
substances, as salicine, sugar, starch, stearic acid, is known by the color-
less solution which takes place in concentrated sulphuric acid. The
presence of a?mnomaca7 salts is revealed by the odor which ensues on
the addition of caustic alkali.—Brit, and For. Med. Chir. Rev. from
Revue Medico- Chirurgicale.