ON QUINOIDINE. 
41 
ART. XII — .ON QUINOIDINE. 
By Mr. Redwood. 
Since the publication of the fact that the amorphous 
quinine, for which a patent has been taken out in this 
country, is neither more nor less than the substance which 
has long been known in commerce under the name of 
Quinoidine or Chinoidine, numerous inquiries have been 
made as to the difference, if any, in quality ', between the 
patented preparation, and the quinoidine in the state in 
which it is met with in commerce. Most of the wholesale 
houses are now supplying quinoidine at one-fourth the 
price of the patented amorphous quinine, and there can be 
no reason why the former should not in all cases be substi- 
tuted for the latter, if it be found to be equal to it in quality. 
It has been already shown that quinoidine and the pa- 
tented amorphous quinine, are both mixed products, con- 
taining several proximate principles, and that one part of 
these principles is soluble, the other insoluble in ether. 
Even the part which is soluble in ether, is found, on ex- 
amination, to consist of two or three bodies, which, to a 
certain extent, may be separated by crystallization. No 
method, however, has yet been pointed out by which the 
whole of these bodies may be readily and completely sepa- 
rated from each other ; indeed, the task would be nearly as 
difficult as that of resolving a specimen of extract of bark 
into its proximate constituents. 
But although quinoidine and the patented amorphous 
quinine have no more title than some of the medicinal 
extracts to be classed among definite chemical bodies, yet 
we may judge of the qualities of different specimens of 
these substances, by the examination of their physical and 
chemical characters. 
Quinoidine, it is well known, is obtained from the dark 
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