May 17, 1873.1 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
903 
CINCHONA CULTIVATION IN ST. HELENA. 
BY OSWALD A. READE. 
Having recently had a few idle days in the island 
of St. Helena, I took the opportunity of making some 
inquiries respecting the result of the attempt to intro¬ 
duce and cultivate cinchona there. 
The experiment was commenced rather more than 
four years since at the recommendation of Governor 
Elliot who then had charge of the island. The plants 
were at first placed under the management of Mr. 
Chalmers, formerly of Kew Gardens, hut he had left 
the island a few weeks previous to my visit. Every¬ 
one I spoke to in Jamestown respecting them informed 
me that they were a complete failure ; hut as very 
few had actually seen them, I resolved to go to Diana’s 
Peak where the attempt had heen made. 
Diana’s Peak is the highest point on the island, 
being nearly 3000 feet high and six miles distant 
from the town. The south-east trade-winds laden 
with moisture condense in almost perpetual clouds 
about the peak, and people living near the base of it 
informed me that there had not heen a fine day for 
two months. The roads were in such a wretched 
condition that I was obliged to give up my first 
excursion in despair, and renew the attempt two 
days later, though they were then not much better. 
Steep clayey paths seldom trodden by anything save 
cattle, into whose tracks we sank over boot-tops, led 
the way to the foot of the peak. At some remote 
period steps have been cut out of the rock to enable 
people to reach the summit, but many of them have 
been worn away and those which remain are thickly 
covered -with succulent lichens, which render the 
climbing tedious and dangerous, especially near the 
summit, where the path, which is only two or three 
feet wide, is bounded on either side by precipi¬ 
tous slopes. It is along side paths leading from the 
one I have described that the cinchonas are planted; 
everything around them betokens rich and luxurious 
vegetation ; tree ferns and their smaller brethren 
rise everywhere, interspersed with cabbage trees and 
wild fuchsias springing from a thick carpet of mosses, 
the whole boimd together with brambles and some 
scrophularious creeper. The past generations. of 
these have left a layer of rich peat,, kept moist with 
the continual clouds and rain, which has formed a 
good natural bed for the cinchonas. 
Originally, more than 1000 were planted out from 
the hothouse where they were raised, but less than 
300 now remain. I was informed by the man who 
at present has charge of them, that when first planted 
out they made great progress and throve well, espe¬ 
cially G. sucdrubra , some of the leaves of which mea¬ 
sured 19 inches long by 15 broad, before the plants 
were twelve months old. After the roots had pene¬ 
trated through the layer of peat, however, many of 
them began to sicken and die, the heavy red clay 
which underlies it apparently not being suitable for 
them. It is to this I believe that the loss of so many 
cf the plants is attributed.. 
Several species were tried* of tliese (7. succm ubi ct 
has succeeded much the best, and the trees of this 
species which are now alive look healthy and pro¬ 
mising. , , . , . 
G. Condaminea also looks healthy, but the wood 
has grown spindly. 
C. Calisaya has not done so well. 
The average height of the trees is now about 8 
feet. The trunks have formerly been protected for 
2 or 3 feet from the ground with a thick covering of 
moss, but it appears to have been allowed to fall 
away lately. 
The bark has been stripped off some of the dead 
plants and sent to the civil hospital here, where it 
was tried and pronounced to be equal in quality to 
that supplied through the wholesale houses. 
It certainly seems as though the cultivation of the 
red cinchona would be a success in St. Helena, were 
it well looked after. 
NITRATE OF ZINC AS A CAUSTIC.* 
BY M. LATOUR. 
Up to the present time nitrate of zinc has not been used 
as a therapeutic agent; yet its causticity approaches nearly 
that of chloride of zinc, which renders such important 
services in the surgical art. Less soluble than the chloride, 
it is still soluble enough to allow of the hope that its ap¬ 
plication as a caustic will give results sufficiently satis¬ 
factory to recommend it to the notice of surgeons, with 
whom it will rest to decide by clinical experience whether 
it will be of real service. 
Preparation of Nitrate of Zinc .—Pure nitrate of zinc 
is easily prepared by dissolving commercial zinc, with the 
aid of heat, in nitric acid diluted with an equal volume of 
water. It is best to maintain an excess of zinc and to 
concentrate the liquor down to the production of an ochra- 
ceous precipitate due to the formation of a certain quan¬ 
tity of basic nitrate, which carries down the iron usually 
present in commercial zinc. Boiling water is added to 
dissolve the salt, and after cooling the liquid is filtered, 
then evaporated at a gentle heat until a slight ebullition 
takes place. It is now allowed to cool, when the solution 
forms a mass; finally, the salt is separated, broken into 
small pieces, and thrown on to a glass funnel to drain. 
Thus prepared, nitrate of zinc corresponds to a crystalline 
salt melted in its water of crystallization, part of which is 
driven off by a moderate heat. It contains three equiva¬ 
lents of water; it is not completely soluble in water in 
consequence of the formation of a small quantity of basic 
subnitrate of zinc, of no importance otherwise. It has the 
advantage over acetate of zinc of being less deliquescent, 
while its preparation is more easy and less costly. The 
salt so obtained is the basis of the following prepara 
tions :— . 
Paste of Nitrate of Zinc .—A caustic paste is prepared 
by dissolving 100 grams of the nitrate in 50 grams of 
water, and incorporating with the solution 50 grams of 
wheaten flour. The mixture is kneaded until perfectly 
homogeneous, and the result is a convenient paste which 
retains its humidity. It does not adhere to the fingerb, 
moulds perfectly wdthout contraction,.and does not spread 
at the edges through attracting moisture from the air. 
When made into cylinders it must not be dried in a stove, 
or it becomes yellowish in colour and friable, through the 
oxidation of the gluten of the flour by the decomposition 
of the nitrate of zinc under the combined influence of heat 
and water. The paste may, however, be preserved in per¬ 
fectly dry cylinders by placing it in a well-closed tin box, 
together with some pieces of quick lime, in such a manner 
as not to come into contact with the lime. 
The preparation of this paste may be shortened, by em¬ 
ploying a saturated solution obtained by stopping the 
evaporation of the solution above described when it has, 
while warm, from 1-450° to 1-580° density; after cooling, 
its density is from 1-630° to 1-650° One hundred cubic 
centimetres of this solution would contain 113 grains of 
the zinc nitrate; a litre of saturated solution would con¬ 
tain 1-130 kilos, and require 555 grams of wheaten flour 
to form a homogeneous paste similar to that before de¬ 
scribed. Upon adding the flour to the solution, the mix¬ 
ture at first is liquid, b ut afterwards it gains consistence 
* Journ. de Pharm. et de Cliimie’ [4], vol. xvii. p. 385. 
