34 
APPENDIX. 
Howard, one of the students of cinchonas best qualified to judge on chemical and pharmaceutical grounds, shares Weddell's 
conclusion, at all events so far that he does not consider the liber fibres, but the parenchyma, as the site of the alkaloids. I 
intend to explain Howard's views in another place, as thexj almost entirely coincide with my own. 
Wigand asserts precisely the opposite view in his excellent ‘Lehrbuch der Pharmakognosie,' page 112, “Alkaloid, that is to 
say quinine, has its seat within the liber, in the liber fibres." No other pharmaceutist expresses himself with so much decision on 
this subject, and he grounds his assertion on a course of acute and careful experiments.* 
Wigand's assertion demands the greater consideration, since it is a repetition of Schacht's saying, f “ I consider it probable 
that all alkaloids are products of the bast cells, and that quinine and chinchonine are only produced in the liber fibres of 
cinchonas." 
With the first clause of this general assertion we have nothing to do; let us consider the second in its relation to cinchonas. 
By experiments, which I need not repeat, Wigand discovered that the liber fabric had a power of absorbing and retaining 
the dye of cochineal in the same manner as a dyer's mordant. As it followed from his experiment that the liber fibres and not 
the parenchyma possessed this faculty, he concluded that the former must necessarily be the site of the alkaloid. I have, however, 
followed his experiments, and cannot say much for them. Wigand summarily rejects Weddell's argument, that the thickness of 
their cellular walls renders this quality impossible. He considers his own method rather intricate, and says it would be well, if 
possible, to find a simpler one. 
He first found that the well-known reaction of Grahe became evident upon heating a cross-section of cinchona bark ; and 
further, that it was possible so to divide pounded bark in a sieve as to obtain separately the parts richest in bast cells and the 
parenchyma. It was then evident that the latter was the poorest in alkaloid. J What follows will show that I must be allowed to 
doubt the validity of both these arguments in favour of Wigand's hypothesis. 
I miss the microscopical proof that there had really been a division in the manner spoken of, and acknowledge that I was 
unable to accomplish it by the same means. In the common G. Galisaya plana, for instance, the parenchyma is usually entirely 
absent. Wigand's own confession,§ “If it were possible entirely to clear the parenchyma from the liber fibres, it would probably 
yield no alkaloid," shows that he himself was not fully satisfied with the result of the sieve experiment. 
If, starting from the fact that the liber fibres are heavier than parenchyma, a piece of bark is taken, with rather long, 
numerous, and, if possible, isolated liber fibres, contained in tender parenchyma, a much more effectual separation will take place 
by washing. 
I chose a variety of C. Galisaya {Boliviano) which is very brittle, smooth, and open, and which, in contradistinction to ordinary 
G. Calisaya , contains a good proportion of parenchyma and many laticiferous vessels. I touched small triturated portions of this 
bark with a little cold distilled water, rinsed away the loose parenchyma, rubbed the remainder again very gently, and treated 
it in the same way. Finally, after a little help with the pincers, I obtained liber fibres, which showed, when microscopically 
examined, only inconsiderable remnants of parenchyma, and were themselves uninjured. 
The separated parenchyma was, however, less pure, it being almost impossible to clear it entirely from isolated liber fibres. 
The G. Boliviano thus dealt with yielded plentifully the red sublimate of Grahe' s experiment, when heated in a glass tube, and a 
tolerable quantity of alkaloid came from the bark when touched with cold spirits of wine. 
The separated liber fibres showed none of the reaction of Grahe, and even hot spirits of wine drew no alkaloid from them, 
whilst the parenchyma gave results in both respects similar to those of the unchanged bark. I made the same observations with 
C. land folia. It seems to me that this simple experiment proves, at least, that the woody liber fibres are not the sole or 
principal site of alkaloid, but far rather the parenchyma is so. There are, it seems to me, very few possible objections against 
this proof. 
Wigand's assertion, that the liber fibres turned red when heated, is no doubt the result of his having worked with 
parenchyma as well, when the red sublimate from the latter might easily colour the liber fibres ; but it may be said that Grahe's 
reaction is not a sufficiently delicate test to be of much account. 
The question is not, however, to prove the absolute absence of alkaloid in the liber fibres, but much more its preponderance 
in the parenchyma. Nevertheless, I tried a few experiments which proved that in dried sago meal less than one per cent, of 
sulphate of quinine cannot be discovered by Grahe's reaction. The delicacy of the method, however, goes further with the bark 
itself, since it gives positive results if, for instance, G. Boliviano is mixed with five times the weight of sago. Since by Grahe's 
proof no alkaloid was to be found in the liber fibres, but was present in the parenchyma, can it be doubted that the latter yields 
the principal part of it. But the fact that spirits of wine drew no alkaloids from them deserves to count for much more. If 
alkaloid is contained in parenchyma, no one wishes to assert that the liber is wholly destitute of it. Even should this be the case 
in the living plant, it is highly probable that as the bark dries, small quantities may be absorbed by the liber fibres. In fact 
my liber fibres, which seemed by ordinary treatment to contain no quinine, show slight traces of it by influorescence. Of how 
much account it is, however, to obtain slight traces of quinine in this optical way, can be imagined when it is remembered that 
the one-hundred-thousandth part of a milligram discovers itself in this manner. It is hardly necessary to remark that parenchyma, 
filtered with sulphuric acid, showed very evident fluorescence. A most serious fault might be found with the means of procuring 
my liber fibres, since of course cold water, even in the very smallest quantities, takes some alkaloid from the bark. The 
circumstance can only be thought of no consequence when it is remembered that I used it with great caution for a very short time. 
And at the same time it cannot be imagined that the liber fibres should thereby lose all their alkaloid and the parenchyma retain 
it. But even grant that an even amount of alkaloid is lost in the process by both structures, this does not in the least alter the 
conclusion that the pa/renchyma contains the larger portion. 
* ‘ Botanische Zeitung,’ vol. xx. pp. 137-143. + Schacht, ‘ Anatomie und Physiologie der Gewachse,’ Berlin, 1840, vol. i. p. 400. 
X The opposite is shown by Howard’s experiments on China rubra dura. Compare ‘Nueva Quinologia,’ Microsc. Obser. fol. 5. 
§ ‘ Botanische Zeitung,’ vol. xx. p. 140. 
