INAUGURAL ADDRESS. 
113 
bark has been carefully removed.* The wood thus laid bare exudes a delicate 
cellular tissue, having the aspect of minute gelatinous drops, which gradually 
increasing and hardening, ultimately forms a continuous layer of new bark:— 
and now comes the interesting fact that this new bark is richer in alkaloids 
than that which it replaced; and bark of the second renewal is richer than that 
of the first, and of the third than that of the second. “ Is this state of things ” 
says Mr. Howard “ to last and become permanent, so that by continually strip- 
“ plug the trees of portions of their external covering, it should become in the 
“ same proportion more rich in the very product that we need? This seems 
“ very improbable, yet it is the conclusion to be arrived at from the above ex- 
“ periments.” 
The increase of alkaloids, let me observe, is not trifling but in extreme cases 
is almost double. It is also stated that bark the third time renewed is better 
fitted for the extraction of quinine than normal bark, and yields the alkaloid 
in a state in which its purification is singularly easy. 
Mr. Broughton whose assiduity in this field of research continues unabated, 
made experiments on two trees of Cinchona succirubra which showed that when 
the trunks were deprived of light for some months by being covered with tinned 
plate or black cloth, the amount of alkaloids increased more than 50 per cent; 
the proportion of quinine however remained almost stationary, the increase 
being in the shape of cinchonine and cinchonidine. In bark renewed under 
moss, an improved proportion of quinine is found. 
The cultivators of madder are in the habit of covering up with earth the 
lower portion of the stems of the plant, finding by experience that deprivation 
of light tends to develope the peculiar colouring matter for which the plant is 
valued. It has been observed by Decaisne in examining microscopically the 
roots and stems of madder, that the cellular tissue of the former contains a 
yellow liquid, while that of the latter is filled with green colouring matter ; 
and he has been able to prove by experiment that it is possible to change at dis¬ 
cretion the production of chlorophylle and to cause the elaboration of the 
colouring matter of the root in its place. It happens in this case observes Mr. 
Howard, that the green portions which when exposed to light, absorb the car¬ 
bonic acid of the air wTilst diseugaging oxygen, absorb, on the contrary, when 
deprived of light, the oxygen of the atmosphere which surrounds them and re¬ 
place it -with carbonic acid. Does not something analogous take place in the 
Bed Bark tree, the shading of the stem of which is attended with such mani¬ 
fest advantage ? 
In Mr. Broughton’s Report to the Madras Government , the following interest¬ 
ing fact is relatedamong the Crown-bark trees (Cinchona officinalis L.) 
raised from seeds collected by Mr. Cross, there "were observed to be a few having 
narrow, lanceolate leaves and a somewhat different aspect from their compa¬ 
nions. A comparative analysis of the bark of these two forms of Cinchona 
(growing side by side and raised, as it would seem, from the same lot of seeds) 
afforded this interesting result,f—that that of the tree with lanceolate leaves 
* The entire removal of the hark from a stem is a destructive practice never adopted in 
India. 
f Mr. Broughton’s analysis of these barks may be thus stated:— 
Bark of tree with Bark of adjoining trees 
lanceolate leaves. of Cinchona officinalis. 
Quinine.. . 7 T 5 . 2-06 
Cinchonine and Cinchonidine .... 0'8o. 2‘42 
Total of alkaloids per cent 8 - 00 .4-43 
Sulphate of Quinine obtained crystallized 
VOL. XI. 
7-37 
undetermined. 
I 
