MICROSCOPICAL OBSERVATIONS. 
LIBRARY 
NEW YORK 
BOTANICAL 
GARDEN. 
It is important to observe that the whole of the sections in the first two Plates, and partially those 
in the third, are of the same species, C. succirubra, Pavon. It is evident on inspection that, whilst a 
certain family likeness prevails amongst those barks which have not been subjected to unnatural circum- 
stances, there is yet some variation in the size and manner of dispersion of the fibres of the liber 
and of the laticiferous vessels; so that attempts to classify barks according to a too-precise system, 
resting specifically on such distinctions, would certainly end in confusion. In the renewed barks 
the characteristics are in part less distinct, so that the renewed barks of G. succirubra and of C. officinalis 
are seen to be much more like each other than they are to the species to which they respectively 
belong. 
The external appearance of the specimens varies according to their place of growth. In Plate I. 
Pig. 1, the circumstance of being grown under dense shade gives the bark a suberous aspect, that of the 
China rubra suberosa of the Germans, which Dr. Berg derived from a separate species, the C. coccinea of 
Pavon.* It is well known to those who are familiar with the C. succirubra in its native forests, that the 
bark of the same tree will assume these different aspects, as it grows in a more or less exposed situation. 
The bark of Pig. 2 had more the aspect of the Cortex Chinee ruber durus of Berg. That of Pig. 3 is 
remarkable for its poor appearance, and for the ease with which the external coat exfoliates. 
The crystals of alkaloid are distinguished from those of raphides, which are found in the abnormal 
concretions, by their aspect and by the circumstance of their easy solubility in glycerine, in spirit, in water 
or in any menstruum which I know how to employ. They also polarize feebly, and present the appearance 
of different salts of quinine and other alkaloids present in the bark, which apparently the feeble alkaline 
ley has not at once been able to reach. The Pig. 1 section, remarkable for its abundance in cincho- 
nine, is also remarkable (as I found in some thick sections) for an abundance of a peculiar concretion 
of crystalline masses in the region of the liber. These are not seen in Mr. West’s figure, having been 
removed by the caustic. I presume that the crystals found in Pig. 2 and Pig. 3 belong to the salts of 
cinchonidine, though the facies of the crystals most resembles those of the alkaloid itself. 
In Pig. 8 we find the appearance of a salt of quinine, and that chiefly in the cellular envelope. 
In Pig. 8 a the character of the crystals is more fully brought out, and contrasted with the earthy salts 
which fill some of the cells. 
In Plate II. we are presented with the features of bark in varied stages of renewal. That in the 
early stage (Pig. 1) appears to be as yet very little organized, consisting almost entirely of ordinary cellular 
* JBerg’s c Anatomischer Atlas/ p. 64 ; note. 
b 
