ON QUINOIDINE. 
33 
ART. VIII.— ON QUINOIDINE. 
By Dr. F. L. Winckler. 
In the year 1843, the author discovered that commercial 
quinoidine contained, besides more or less cinchonia and 
quinia, also a very large proportion of an alkaloid which 
was apparently in combination with two different coloured, 
amorphous, resinous substances. This alkaloid was amor- 
phous, and yielded only amorphous salts; but in other 
respects it did not differ from quinia, and had exactly the 
same combining weight as the latter. The author therefore 
recommended it to be purified and employed as amorphous 
quinia in the same way as common quinia. He is, how- 
ever, of opinion, that Liebig (who has recently proved by 
ultimate analysis, that these two bodies have the same 
composition) overvalues the importance of quinoidine. Dr. 
Winckler obtained from eight ounces of crude quinoidine, 
only three ounces of pure, white, amorphous quinine, so 
that no great pecuniary advantage can be derived from it ; 
whilst, on the other hand, the crude, and certainly cheap 
quinoidine should not be employed, on account of its varia- 
ble composition, and its liability to adulteration. 
Crude quinoidine having such a variable composition, 
cannot always be obtained pure in the usual way, by dis- 
solving it in alcohol, ether, acids, &c.; the author tried, 
therefore, to destroy the foreign substances contained in it, 
by sulphuric acid of sp. gr. 1.83 — 1.84, since the latter 
affects neither the amorphous nor the crystallizable quinia, 
nor cinchonia. Fijiely-powdered crude quinoidine was 
mixed in small quantities with an equal weight of sulphuric 
acid, so that each portion was separately dissolved before 
the other was added, an operation not easily performed, 
since the powder conglomerates almost always, as soon as 
