CHEMICAL AND MICKOSCOPICAL INVESTIGATIONS. 
27 
I liave previously copied* from Dr. De Vrij a table showing the relative proportion of kinova-bitter in 
the different parts of the Calisaya, and I may here add a more recent observation of the same chemist, that 
the leaves of C. succirubra grown at the low elevation of Peradenia (1600 feet above the sea) contained 
twice as much kinova-bitter as leaves of the same grown at Ootacamund (7416 feet), preserving still the 
same inverse ratio to the proportion of alkaloids which pervades the whole structure of the plant. 
The Mother-substance of the Cinchona. 
This substance is found only in the wood ; it does not coexist with the Cinchona-red, and but in a 
very minor proportion with the alkaloids, but on its breaking up into Cinchona-red the formation of the 
alkaloids seems in some way to depend. It is then, at all events, worthy of close investigation. 
The Cinchona-red is produced by a process of slow oxidation in the bark of the plant. This 
process, as I have shown, is very gradual, and is by no means complete when the dried bark comes into 
the hands of the chemist. It must be remembered that this change does not commence in the wood, which 
retains its yellowish hue unchanged, but the bark assumes either a reddish f appearance (as in the species 
we are considering), or more or less tawny, ii the Cinchona-red is masked by other principles. This 
Cinchona-red is found in all the valuable Cinchona::, although in part replaced in the aricine-producing 
plants by a kindred substance of intensely orange colour. 
The process which I found most advantageous to extract the colouring matter from the wood was to dis- 
solve it out by ether, which, as a neutral substance, seemed incapable of exercising any influence on its 
chemical composition, and was consequently best adapted to give it into my hands in a state of purity, and, 
as far as first appearances went, of homogeneous composition. On evaporating the dissolving medium, the 
substance was left in appearance resinous, brittle, almost inodorous, and perfectly stable in its composition 
under all circumstances. It does not attract moisture nor absorb oxygen from the air, and thus differs 
sensibly from the Cinchotannic acid found by Schwartz in the Calisaya bark, and which he rightly described); 
as passing rapidly under the influence of ammonia and of the oxygen of the air into Cinchona-red. 
The present substance must nevertheless stand in very near relation to that of Schwartz, but also in equally 
near relation to another substance which he derived from the same bark, and which he calls Chinovic acid.§ 
Schwartz considered this to be identical with a substance (Quinovin) previously found by TIlasiwetz|| in 
the Quina nova. 
The proof of the near relationship existing in this Mother-substance to both Cinchona-red and Kinovic 
acid is found, first in the action of alkalies, metallic oxides, or alkaloids, which produce the red colour by 
their action on the mother-substance. Thus the addition of ammonia to the light yellow ethereal solution 
o-ives rise at once to a fine rose-colour, and when all is evaporated down together, there remains a compound 
of kinovic acid and ammonia coloured by Cinchona-red, which appears as an excretory product. The 
powerful alkalies break up the substance in this manner at once, but the operation of earths and metallic 
oxides is more slow. Thus, when a piece of lime is dropped into the ethereal solution and allowed to stand 
in the sunlight, which seems to favour the process, the Cincliona-red is very gradually deposited on the 
lime, which assumes nearly the appearance of red coral ; and in this case nearly the whole of the Mother- 
substance seems to pass in time into Cinchona-red, and it thus appears to contain the elements of cincho- 
tannic acid; but when lime-water is made to act upon the same substance, it dissolves this with the 
* Illustr. Nueva Quinologia, svb voce 0. magnifolia. 
f The appearance is exactly described by the Spanish name of the best Red Bark, la teja, i.e. resembling a tile ; another 
kind, equally abundant, of a different aspect, which I have described, is called la morada, with equal propriety. This latter, accord- 
ing to Mr. R. Gross, who gives me the above information, is of a different species to the 0. succirubra (? 0. conglomerata) . 
J f Annalen der Chemie und Pharmacie/ lxxx. p. 332. § ' Centralblatt/ 1852, p. 194. 
|| Ann. der Chemie und Pharm. lxxiv. p. 138. 
