50 
*rHE THOPICAL 
AGRICULTURIST. 
fJCLY 1, 18BB 
the Buppoeilion that ■with extended experience they 
will produce an article which is as merchantable as 
any. Moreover, Mr. John Smit Sibniga, the director 
of the Langen-Ardjo plantations, to whose " mani- 
festo " we alluded in our iaaue of February 12 (page 
288), has successfully carried out his combination 
amongst the planters, who have contracted with the 
Bandoeng works to supply a ceitaiu proportion of 
their output to the BnucfoeDg works, against pay- 
ment on a sliding-Bcale, varying with the prices 
obtained from the manufactured product ; they also 
agree not to supply any bark to otlier quinine- 
manufacturers without the coneent <if the Bandoeng 
works. The latter have secured the orders from 
the Netherlands-Indian Government, and the re- 
mainder of the manufaitured quinine is sold for 
collective account by a wealthy firm in Samarang. 
The following, according to a writer in the l^lmrma- 
ceutinoh Weekilad, is tne method of manufacture 
adopted in the factory : — 
At present only sulphate of quinine is produced, 
but the intention is to e.^tend the scope of the works 
soon, and to add the manufacture of hydrochloride of 
quinine, &o. Ledgeriana is the only bark used, and the 
different parcels are mixed in such manner that the 
contents are always approximately 5 per cent. The 
bark is then ground to a fine powdrr, and mixed with 
about 50 per cent, of slaked lime and a eufficient quan- 
tity of water to give it a consi^rtency which allows it 
to be transported in baskets to a vertical tank con- 
taining a certain quantity of mineral oil. This oil, of 
a sp. gr. of 0 92 and a boiling-point of i:^0 dg. C , dis- 
solves the alkaloid in a proportion of about J to 1 per 
cent. The tank is heated by means of a coil, 
through which steam is passed for about half an hour. 
When steam i.q shut off, the .mixture separates readily 
into two layers, of which the upper — i-e., the oil, 
which now holds the alkaloids in solution — is drawn 
off : the remainder is again heated, in order to 
separate any oil that might have been left. 
The oil is then pumped into another 
reservoir, and warmed with a quantity of 
1 per cent sulphuric acid, which removes the alka- 
loid, The acid solution of tiie sulphates is then 
drawn off, again heated, and almost, but not quite, 
neutralised with either ammonia or soda. As soon 
as it is sulificiently concentrated, it is run into sballow 
dishes holding about 5 to 6 gals., and there left to cool, 
by which means the crude sulphate of quinine crystal- 
lises out. This crude product then passes through a 
centrifuge, and the residue is washed, and afterwards 
purified by treatment with charcoal and re-crystallise. 
It is then dried and packed for export. 
So far, we understand, the company is satisfied with 
the results of the sales of its product in Europe, and 
regular shipments have been arranged for. The pro- 
ducers are apparently content to sell their product at 
less than secondhand prices of German quinine, and it 
has been eagerly bought ht;re for mav.ufactnriiig-piir- 
poses, so that its future is practically assured. Their 
principal danger is that of being squeezed out by the 
European manufactures, but the latter do not appear lo 
have given any indication of moving in that (.direction, 
perhaps because of their failure to move the Java people 
otherwise. In any case, dear quinine appears to be a 
remote possibility. 
THE IMPOETS OF COCOA. 
By the courtesy of the Chancellor of the Exche- 
quer we have been favoured with the exact figures 
of the duty paid on the imports into this country 
of raw and manufactured cocoa, as referred to in hia 
Budget speech. The particular feature of tha t speech 
which interested us was the statement that the im- 
ports of "manufactured" cocoa were three times as 
great in the last financial year as they were two 
years ago. This was rather unexpected. We thought 
it was the home- prepared cocoa which was growing 
in favour. The following are the ex'.ct figuies re- 
c orded at the Statistical Office of the Customs House ;— 
Net Duly received on Cocoa, Tlaic aud t'reperei, in the 
I'wo tiiinnciat t/eais lH9Ci 96 and Iti97-V(i. 
1895-96 1897-»8 
X t 
Cocoa, raw .. .. 103,iOD 116,134 
„ prepared .. 21,032 66,818 
Total .. 124 535 182,647 
The duty raw cocoa being Id per lb. and that 
ou manafactured cocoa 2d per lb , it appears from 
this statement that while our imports of r»w cocoa 
bad increased by 3,103,440 1b. those of cocoa manu- 
factured abroad had increased by 5.421,720 lb. a not- 
able aud not very easily explainable fact. — Chemitt 
aud JJruycfist. 
FIGHTING PESTS WITH PAR.^SITES. 
The greatest single ioduatry of California in fruit- 
growing, says the Syihity Hail, aud the imporiauce 
of this industry has led to the study of every method 
which would increase its profits or lessen its ex- 
Eenses. In this stadiea that of economic entoiuolo{ry 
as taken a foremost place, for the most obJurale 
and expensive enemy the orcbardiat h&s| to combat 
is the myrial insect pests thai attack hira at every 
point and leescn bis profits cu all sidei. 
The result of years of careful study and eonti- 
nuous fighting with spr lys and wa^heis and gases is 
what m.iy be called the California method — :bat of 
fighting insects with insects — a sort of homoeopathic 
remedy of like curing like. Wherever insect pesto 
have become destructive, efforts to find and intro- 
duce their natural parasites have been made, aud 
usually with good results. Artificial methods are 
resorted to as a temporary expedient until better 
means could be had. 
Throughout all Nature there exists a perfect sys- 
tem of checks aud counter checks. : ud otherwise re- 
dundant life is kept down aud the balance prenerved. 
It is this fact that the Califoruians endeavourto take 
advantage of. The worst pests that are known there 
are all imported varieties. They were brought into 
her borders when California, ambitious to become the 
garden of the Union, imported all varieties of plants 
from every part of the world. In very mauy cases 
they were destructive varieties of insects without their 
natural parasites. Removed from their natural ene- 
mies these pests increased with wonderful rapidity 
and became a threatening danger. 
One of the worst of these was the now well-known 
cottony -cushion scale (Icerya pnrchasi), which at 
one time threatened the total destrnction of the 
orange orchards of the State. All artificial melhoda 
of combating this pest were unavailing. At list it 
was suggested that, in as much as the scale had been 
brought from Australia, where it was native and not 
a pt-st, there must be some natural parasite whi-th 
kept it in check. Upon tiiis suggc-stiou ucuon wa-J 
taken, and the now famous Vet'aiia caidiaalls xvaa 
introduced. The result of the labours of this one 
little patasite is that California will this year ship 
12,000 carloads of oringes, whereas she would have 
hp.,d none had it not been for its labours, for the 
shipments at one time fell to 600 cars, aud scores of 
orcha.rds were being cut down and burned. 
The wonderful success of this importation of para- 
sitic friends led to the further study of parasitism 
in insects, which was aided by the State, and large 
importations of parasitic insects have been made, 
with varying but usually good results. In some cases 
parasites have been introduced with the scales thtm 
selves, and in these casf-s the spread of the pctt 
has not been rapid. In other cases natural parasites 
hive adopted themselves to new conditions, and 
attacked the imported insects. There are now very 
few scale insects in Culiforuia which do not have 
some pirasifces. There are sectionr-, however, in which 
the p;ii'asites have not got a foothold, and the pests 
increase rripidly, while in some cases the scale increa- 
ses beyond the power of the parasite to keep it in 
check. But, as a rule, the effort to introduce and 
