ON THE PURITY OF SULPHATE OF QUININE OF COMMERCE. 
213 
It is very interesting to see the particles all arranging themselves into the 
respective groups ; the long slender needles of the quinine salt, the round crys¬ 
talline masses of the quinidine, and the large well-formed prisms of the cinchonine 
Sulpliocyanide of quinine. Sulphocyauute of quinidine. Sulpliocyanide of cinchonine. 
(450 diam.) (450 diam.) (450 diam.) 
salts. So remarkably constant is this reaction, that an observer who has once 
been accustomed to the general appearance can at once say with ease, this is 
quinine, this quinidine, and that cinchonine. 
Sulpliocyanide of potassium is not usually kept by druggists, but may readily 
be made thus :— 
Cyanide of potassium (fused), 
Sublimed sulphur, of each 120 grains. 
Distilled water, an ounce and a half. 
Boil in a glass flask for fifteen minutes, filter, and make up the quantity to 1^- 
ounces with sufficient distilled water. 
This notice of the qualitative analysis ought not to be passed without men¬ 
tioning a very good application of Professor Stokes’s fluorescent test for the dis¬ 
covery of quinine and other substances possessing the property of epipolism. 
A small Geissler’s vacuum tube is surrounded by a longer glass tube which is 
capable of being closed by a cork, an arrangement that permits the tube to be 
filled and emptied as an ordinary phial bottle. When any bark is suspected to 
contain quinine, etc., an acid or alcoholic infusion is put into the outer tube, 
and a spark from the Huhmkorff’s coil passed through. Instantly the fluorescent 
salt, whatever it may be, will show its presence in the most gorgeous manner. 
By this method twenty-seven samples of barks were qualitatively tested in a 
couple of hours that were supposed to contain a new alkaloid, which occurs in 
an Australian tree possessing very peculiar fluorescent properties. 
The process most applicable for the quantitative analysis of sulphate of qui¬ 
nine is that by means of the iodide of potassium reaction, recommended by Dr. 
De Yry some time since. The following was the arrangement employed in the 
present instance:— 
Into a tube containing 120 minims of distilled water and 16 minims of dilute 
sulphuric acid (British Pharmacopoeia), add twenty grains of the sulphate of 
quinine to be tested. When dissolved add 80 minims of solution of hydrate of 
soda (1 to 12) and 300 minims of pure sulphuric ether mixed with six minims of 
alcohol. 
Agitate well, and lay aside for twelve hours ; decant the ethereal solution and 
evaporate for the quinine. To the remaining aqueous solution add just sufficient 
acetic acid to neutralize the alkali, and precipitate with solution of iodide of 
potassium (1 to 4), filter, dry, and weigh the hydriodate of quinidine. One 
hundred grains of this salt contain 71 ’68 of pure quinidine. To the filtered 
solution again add hydrate of soda till decidedly alkaline, when the cinchonine 
and cinchonidine will be precipitated if present. 
