586 
ON THE ALKALOIDS IN CHINCIIONA BARK. 
in ether, contains less kinovic acid, and the substance, separating with lime, is 
no longer pure chinchona-red. 
Now it is possible, both by synthesis and analysis , to obtain presumptive 
evidence that the crystals seen in Red Bark are in the above state of composi¬ 
tion. By synthesis , because by the addition of an ethereal solution of quinine to 
that of the mother-substance, a red-coloured compound ensues, which is capable, 
though with difficulty, of being crystallized from water, with separation of the 
chinchona-red, and also from spirituous media. By analysis , since the same bark, 
treated in exactly the same manner with Liq. Potass, and then boiled with 
spirit of wine, yields Quinine, Cinclionidine, and Cinchonine. 
We have next to consider whether one, or more than one, of the alkaloids are 
perceptible, and to assist in answering this question, I must beg your readers to 
compare my plates with those in Mr. Stoddart’s paper u On the Purity of Sul¬ 
phate of Quinine of Commerce.”* I think that the correspondent forms will at 
once suggest the analogy which is probably the true one. The small tufted 
groups of crystals are quinine, (quinidine, when combined as above, has much 
the same appearance, but was not present,) and the larger and coarser crystals are 
in all probability cinchonine. It is not at all unlikely that cinclionidine may 
be indicated in some of the small aggregations of crystals. These crystals pre¬ 
sent a pleasing and varied appearance under the microscope, but I have not yet 
succeeded in making permanent preparations, since the glycerine which I gene¬ 
rally employ gradually dissolves most of them, and I have not yet found any 
medium free from this objection. I had some specimens mounted in cells in pure 
water, intended for the museum of the Pharmaceutical Society, but found that 
the crystals slowly dissolved even in water. 
Dr. Berg, of Berlin, in a recent publication, remarks, “ The crystals which 
Howard figures, are not found in that manner in the bark, but are first formed 
through chemical treatment of the preparation.” In this, as in most of his ob¬ 
servations on barks, the professor seems to have drawn rather largely on the 
stores of his own insight. I am unable to conceive how it is possible that boiling 
a section of bark for two or three minutes in an exceeding weak caustic solution, 
washing with abundance of distilled water, and placing the slice immediately 
under the microscope, could by any possibility produce crystals intersecting 
the cells in all directions,f neither can I understand why it should invariably do 
this in one species of bark and in many others not at all. 
The fact is that Dr. Berg’s mode of preparation empties the cells of all their 
contents , and he cannot believe that anynme has seen what he has not himself 
observed. 
It is necessary for me to remark that Tuffen West, F.L.S., our most skilful 
microscopical draughtsman, was employed in the first instance, and since then 
two others, to delineate the crystals, so that it is no peculiarity either in the 
vision or the microscope of one person that can be productive of inaccuracy in 
the observation. 
I will now proceed to a more particular description of the microscopical 
drawings, which were made by my son John Eliot Howard, jun., with the best 
powers of Powell and Lealand’s make, and the binocular arrangement, which 
affords much clearer defining power in these cases. 
Plate I.—No. 1 is a horizontal section of a portion of a quill of Chinchona 
succirubra , from the collection of Pavon. The drawing No. 1 was made as the. 
object appeared under the half-inch ; in No. 2, under P. and L.’s quarter-inch 
lens. In No. 1 will be seen, as at a , the rather compressed cells of the paren- 
* November, 1864. 
f The bark must previously be macerated in water for twenty-four hours. From the time 
the slice is cut to its being placed under the microscope, less than five minutes should elapse, 
of which two minutes are passed in the boiling solution. 
