ON THE ALKALOIDS IN CHINCHONA BARK. 
585 
small nucleus, and presenting very much the appearance of some compounds of the 
alkaloids in their crystalline form. They evidently are not the product of vital 
processes taking place in the plant in its living state, but must result from 
changes in the juices of the bark after its removal from the tree ;* indeed, it 
can be no surprise if a sap-fluid containing eleven or twelve parts of salts of the 
alkaloids in a hundred should then at least (if not even whilst maturing on the 
tree) betake itself to crystallization. 
‘ ‘ In order to observe these perfectly, I found it necessary that the section of 
bark should not be too thin, as otherwise the action of the caustic would be too 
powerful, leaving only the ultimate structure of the cellular tissue. I compared 
the crystals with those of Cinchonine, Quinidine, and Cinchonidine; but the 
character of the decoction of the bark being always acid, seemed to forbid the 
expectation, which indeed was not realized, of finding the crystals coincide with 
these. At length it occurred to me to compare the crystallized compound of 
quinine, formed, as I have mentioned, under the head Ch. succirubra, by adding 
quinine to the ethereal solution of the mother-substance from the heartwood 
of the tree. I found the crystals, which under some circumstances this com¬ 
pound forms, to agree exceedingly well with those seen in the bark. The feeble 
amount of polarization in the two was a point of coincidence that could not be 
passed over ; and on the whole, it is almost certain that the quinine is in this 
state of combination in lied Bark, since the decoction abandons, by cooling, a 
deposit in which I have ascertained the presence of quinine, chinchona-red, and 
kinovic acid, and after this has been deposited, no trace appears to exist of 
kinate of quinine, the only other probable form. 
u I therefore conclude that the crystals seen in the bark-section are Rinovate 
of Quinine rather than kinova-tannate or cincho-tannate, since the cinclio- 
tannic acid oxidizes off into chinchona-red, and leaves the quinine in combina¬ 
tion with kinovic acid, as an almost colourless salt, such as is seen in the sec¬ 
tion” (as published in the ‘ Quinologia’). It is, however, not improbable that 
the cincho-tannic acid, during its oxidation, facilitates the combination, and 
as the kinovic acid in the different parts of the plant holds the exactly inverse 
proportion to the amount of alkaloid contained, it is difficult to avoid the pre¬ 
sumption that the elements of kinovic' or kinova-tannic acid in conjunction 
with ammonia, which is always present, may give rise to the alkaloids in the 
bark.f 
The mother-substance I have referred to is described in the above work, 
under the head Ch. succirubra. It is extracted unchanged from the heartwood 
of the tree, by the simple action of ether, and appears like a resin when dried, 
having the composition C 46 H 36 O 10 4 In this state it is not deliquescent, differ¬ 
ing in this from cincho-tannic acid, and it is permanent. It may be heated in 
a sealed tube for twenty-four hours with chloride of ammonium without being 
decomposed ; but, by the addition of a few drops of liquid ammonia, the bright 
yellow ethereal solution changes to a beautiful pink colour. By boiling with 
lime and water, it is broken up into kinovic acid (which passes through the 
filter in combination, separating with acids), and into very pure cinchona-red, 
which remains behind with the rest of the lime on the filter. This last is evi¬ 
dently the product of the oxidation of the cincho-tannic acid. The mother- 
substance appears to undergo some change in the roots. It becomes less soluble 
Seven pounds of green give four pounds of dry bark in this species (Ch. succirubra), 
(Spruce, Report, etc., p. 28,) whilst the freshly-peeled bark of the Ch. lancifolia dries to one- 
tbird of its weight (Karsten, Medicinische Chinarinden, etc., p. 17), so much greater, in its 
growing state, is the density of the fluid constituents in the former kind of bark than in the 
latter.” 
f* See, as above, under head C. magnifolia. 
i See my ‘ Quinologia/ under head Ch. succirubra. 
