ON THE CULTIVATION OF CINCHONA IN ENGLAND. 
389 
formidable difficulties in the cultivation of plants so sensitive as these are to the 
deficiency of stimulus in the dreary months of winter, and to the excess both of 
heat and light in our summer above that to which they have been accustomed. 
The effect of different coloured rays, of polarized light, of a greater or less 
amount of actinism necessarily comes into view. 
The leaves of many species are particularly sensitive to light, and turn 
towards the rays of the sun in a manner sufficiently remarkable. In some kinds 
the structure and colouring are very beautiful, and would quite repay cultiva¬ 
tion, with this object in view. They are frequently covered with a lustrous 
epiderm, as described by Dr. Weddell, in reference to the Calisaya. This epi- 
derm seems, as in the case of some other plants, largely composed of wax: 
when this is removed, either by mechanical injury or by chemical solvents, the 
leaf suffers, and the oxidation of the juices becomes manifest. It is not easy to 
imagine from dried specimens, the great variety of structure and characteristic 
peculiarities which the leaves present; but when once well observed, the aspect 
of the plant fixes itself in the memory. 
The respiration of plants, as affected by a too retentive soil or by too abun¬ 
dant application of water to the roots, has to be studied, and it is also necessary 
to mark the period of hibernation or repose, and to encourage rather than to 
interfere with rest at this period, a period which seems in India to be very 
accurately marked, and which even under glass, it is not difficult to trace. 
Then the nutrition of the plants will require much care. It may, at first 
sight, seem requisite simply to provide the needed soil; and very pure sand, 
such as Reigate sand, rich loam, and bog earth, in proportions, varying accord¬ 
ing to the species,—when mixed, as I find desirable, with broken brick,—will suffi¬ 
ciently afford this. But there is more than this; for we shall find, if we study 
the plant, that it is desirable to supply it at the period of its most active vege¬ 
tation with food ministered, as much as possible, in a liquid form, and there¬ 
fore more easily assimilated. For as regards the life and growth of the plant, 
we may, in a certain sense, adopt the saying of Thales, that “ all things are from 
water,” for all things must be in solution (either aqueous or aerial) before they 
can be changed into the living substance of the vegetable. Now the natural 
solvent is rain as it falls from the clouds, and in the normal state (as ob¬ 
served by Weddell and Markham) of the Cinchona * the roots spread superfi¬ 
cially through a loose mass of earth and decaying vegetation, amidst which 
they absorb, together with the rain-water, various mineral substances, and also 
gases, especially carbonic acid, presented to the spongioles in the manner most 
to their advantage. 
M. H. Struve f has recently demonstrated the existence, under certain condi¬ 
tions, of nitrite of ammonia, together with ozone and oxygenated water in 
rain and snow; and M. Deville has found in snow and rain, collected in the 
neighbourhood of the hospice of St. Bernard, a similar composition, at least in 
so far as nitric acid and ammonia being present in greater or less quantities. I 
learn from Dr. Anderson that some species of cinchona flourish at Darjeeling, 
although the rainfall averages 127‘30 inches for the year,:}: of which 82 inches 
fall in three mouths of the summer. But then the character of the soil and slope 
of the hills is such that the rain-water, after having bathed the roots, passes 
away immediately from them; for Dr. Anderson, as every one else, finds the 
Cinchonse to be most impatient of water at the roots. 
This is difficult to imitate, and the change consequent on the scarcity of rain¬ 
water to that derived from springs has (apparently) cost me the health of some 
* The C. succirubra prefers a stronger soil, and, perhaps on this account, is more easy to 
cultivate than some others. 
f ‘ Journal de Pharmacie et de Chimie,’ November, 1869, p. 357. 
J Beardmore, ‘ Manual of Hydrology,’ p. 330. 
