10 
QUINOLOGY OF THE EAST INDIAN PLANTATIONS. 
sugar, albumen, gluten, and other material in solution. But during the progress of vegetation, the propor- 
tion of these matters becomes increased, and when the sap has arrived at the extremities of the plant it 
contains more organic principles than when collected in the vicinity of the roots. In the trees with soft 
wood the ascent of the sap takes place through the whole extent, in others apparently in the sap-wood 
only. This, which is generally called the ascending sap, is attracted to the leaves and to all the external 
parts of the plant, having in itself, it is said, no power to convey nourishment ; but it is submitted in 
the leaves, in a very curious and complicated manner, to the action of the atmosphere and of the light, 
by means of which most important changes occur : carbonic acid is decomposed and the oxygen driven off ; 
chlorophyll is elaborated, together with many other less marked products. The sap, which is fraught with 
these and now fitted for nutrition, and called the descending or nourishing sap {seve nourriciere ) makes its 
way downwards, and is attracted to every part of the plant where its presence is needed, the ordinary 
channel for its course being the portion belonging to the outside of the woody structure and internal part 
of the bark, in which increase very manifestly takes place at every fresh period of the growth of the plant. 
This course of the descending sap may be traced down even to the roots ; and, as I have mentioned in 
previously published remarks, also laterally by the medullary rays, specially near the base of the stem, 
thus furnishing a channel for throwing into the ever-active circulation of the sap some of the substances 
which have been elaborated in the bark, and which may be carried by the ascending current to fulfil 
important purposes in other regions of the plant.* 
If this circulation of the ascending and descending sap be entirely checked, of course the tree perishes ; 
but there seems to exist considerable adaptability in seeking out fresh channels when the old ones are 
partially closed. Thus we familiarly observe old trees, of which the heart-wood has entirely perished, 
carrying on a vigorous ascension of the sap through what little may remain adhering to the bark ; and, on 
the other hand, cases sometimes occur as in the trunk of a celebrated lime-tree at Fontainebleau, (described 
in the ‘Annales des Sciences’ for 1855). This tree was planted in 1780, and in the year 1810 was 
deprived of bark round the trunk for a considerable space; and, although this was so far from being 
renewed that decay affected the wood to such a depth that the diameter of the tree was at length reduced 
by three-quarters, it grew and apparently flourished till the year 1854. In this case the whole circulation 
must have been carried on in the centre of the tree, whilst the surface was being destroyed, showing the 
power of adaptation to circumstances which exists in the vegetable kingdom. An instance of the same 
adaptability, but in an endogenous plant, has just fallen under my notice in an account of the Great 
Dragon Tree [Draccena Draco ) of Orotava, in Teneriffe, described by Humboldt, which perished in a gale 
last autumn. “ When I visited it in February,” says Signor Fenzi, the writer of the description, “ it was 
still in excellent health , — its immense crown covered with innumerable panicles of scarlet fruits, and the 
huge trunk, although completely decayed in the interior , sustained vigorously the spreading mass of fleshy 
branches and sword-like foliage. Its circumference was about seventy-eight English feet, while the total 
height did not exceed seventy-five feet ; and it was remarkable that through some crevices in the trunk 
a small Draccena was seen growing spontaneously in the decayed substance furnished by the parent-tree.” 
The sap must in this case have risen for many centuries in the outer portion of the trunk. 
Having thus rapidly passed under review some preliminary observations in reference to the circulation 
of the sap in plants in general, I now proceed to consider a question which must be looked upon as 
practically important in reference to the cultivation of the Quinine-producing plantations in India. I have 
found by analysis a steady improvement in the bark renewed over spaces that had been previously 
decorticated, having received from Mr. MTvor specimens of the first, second, and third time of renewal. 
Ine structure, as exhibited microscopically,! also shows a manifest and gradually perfected building-up of 
* Ulusfcr. of Nueva Quin. Micr. Obs. p. 2. 
f Mr. Broughton also says (March 16, 1868), “A microscopic examination shows no difference in structure between it and 
the mossed bark.” 
