158 
THE TROPICAL 
AGRICULTURIST. [Sept. I, 1899. 
ing with the Hevea or Para, and we may 
quote the concluding statement : — 
The reason why the base of the trunk should 
yield so much more latex has, I think, something 
to do with the thicker and softer bark at this 
region. This peculiarity has not been only 
observed in Ceylon. In Colonel W. J. feeaton's 
report on the Para rubber trcos of Tenasser'm, 
Burmah, dated Januaiy 28, 1889, he remarks: 
" It was observed that the e.vudation of miJk was 
greatest near the ground, where the bark was 
thickest, while at a height of six or seven feet 
it was almost nil." 
_Mr. Parkin next, takes up the Cas- 
tilloa tree as grown in (Jeylon, and gives 
the results of his experiments as to the 
outflow of the latex. Further on, we have 
"the effect of wounding on the flow of the 
latex," with a further series of experiments in 
tapping, extending up to June 6th last. We 
do not give the details and results, because as 
we reproduce the Circular in full in our 
monthly periodical as well as Manual, planters 
specially interested can carefully study it 
there. Suffice to say that the result seems 
satisfactory, although in conclusion we are 
told :— 
Probably it will be found that under some con- 
ditions it is best to tap daily, while under others 
it is best to tap at intervals of two, three, four, 
seven, or even ten or twelve days. A large num- 
ber of experiments on different methods of tap- 
ping have been made and are still being made 
in the Botanic Gardens, and their results will 
be published later. Those planters who ai-e be- 
ginning to tap their trees might well repeat some 
of the experiments described above on a larger 
scale. The success or failure of the cultivation 
depends chiefly on the yield of milk, and it has 
been clearly shown that this is extraordinarily 
different in diHerent trees of the same size and 
age, and that it may be enormously affected by 
different methods of treatment. Each man must 
find out for himself the method absolutely best 
suited to his trees, in the light of the above 
observations and of his own and those of other 
workers. 
We now come to "the preparation of .Com- 
mercial Rubber from the extracted latex," 
and we read : — 
The two chief points with respect to the pre- 
paration of commercial rubber are to have it free 
from moisture and putrefaction. The first can be 
effected by drying the rubber particles in thin 
sheets ; the second by either removing the proteid 
matter or by the addition of some antiseptic 
substance which prevents the growth of bacteria 
and mould. 
And again ;— 
Considering that the caoutchouc in latex exists 
in the form of minute globules suspended in a 
fluid, and that they are lighter than water, it is 
rather surprising that no one till now has thought 
of the idea of separating the caoutchouc and so 
preparing rubber by centrifugal force, such as is 
used for separating the butter fat of milk. The 
credit of STjplving the idea is due to Mr. BLfFen 
of Cambritlae "University, who, in connection with 
Mr. Erme Howard, recently undertook an ex- 
pedition through the rubber-producing districts 
of America. With a modified centrifugal milk- 
tester they tested the possibility of extracting the 
caoutchouc from several latices with great success. 
Then experiments made by Mr Drieberg at 
the Agricultural 8chool with a cream-sepa- 
rator are referred to ; but sufficient speed 
could not be got to opei-ate successfully. 
Next :— 
In connection with Mr. Biff'en's discovery a 
company has been formed and a large tract of 
land laid down in Mexico in Castilloa, with the 
purpose of producing commercial rubber by cen- 
trifugalisation. A patent has been taken out on 
the machine, and consequently it remains to be 
seen at what price it will be put on the market. 
It may be somev. hat prohibitive. In the meantime, 
let us consider what other meau.s there are for 
prepi;ring good rubber fiom the latex of Hevea 
and Castilloa. 
Accordingly we are told of "Coagulation by 
acetic acid," "Extraction of Caoutchouc by 
means of Mercuric Chloride (corrosive sub- 
limate)". Next we have the effect in deal- 
ing with "Castilloa," and again we are re- 
minded that our Ceylon species "Maikham- 
iana" probably differs from "C. elastica" 
in the properties of its latex; but on the 
whole gi-eater success was attained than in 
the case of Para. Nor is the Ceara to be 
despised, since we read : — 
Manihot Glaziovii (Ceara Rubber Tree).— This 
latex has been shown by Biffen to be also cap- 
able of yielding its rubber by centrifugalisation, 
as well as by churning. 
Finally, we come to the "yield," and we 
are told "there is a great individual differ- 
ence in the trees in the yield per incision. 
Out of the 32 trees of "Para" at Pera- 
deniya, two flow much better than any of 
the rest without any apparent reason. 
Six times the largest quantity of latex got 
from a Hevea in a single incision, has been 
got from a Castilloa rubber tree. (It is ex- 
traordinary how a prejudice could have been 
formed some years ago against the cultiva* 
tion of Castilloa trees in Ceylon !) On the 
other hand, however, the Castilloa latex, 
as a rule, contains only about half the per- 
centage of caoutchouc that than of Hevea 
does. And the results of experiments are 
summed up as follows after giving details 
of tapping of Castilloa trees at Henaratgoda 
at the beginning of March :— 
What time should elapse before the trees flowed 
as well again, has not yet been ascertained. 
Perhaps the trees would not be worth tapping 
more than twice a year. In that case the yield 
of rubber per tree per year from a trunk 3 ft. in 
girth and 12 ft. in length would come to about 
300 grams or 10£ oz., a small amount compared 
to the results stated for its native countr}-. In 
fact, the weight of rubber, would not be much 
greater than from Heveas of corresponding size 
tapped ten to twelve times in the year, but the 
expense of extraction would be very much less. 
Further experiments in tappings— both in 
Government Gardens and on private plant- 
ations—are clearly necessary. We are pro- 
mised a note of results from the Kalutara 
district. 
In his last chapter Mr. Parkin gives us 
some notes on other rubber-yielding trees 
growing at Peradeniya and Heneratgoda, 
none of which, except the African Lcndol- 
|)/was seem to be worth much. At the end Mr. 
:_!is gives ujsome "general remarks" on Mr. 
Parkm's Report, the cream of which we 
extract in the following, although Mr, Willis 
has a good deal more to say : — 
The ideal rubber-yielding tree would be one in 
which there were many laticiferous vessels, all 
communicating freely with one another, and con- 
taining only caoutchouc in an emulsion with 
water. The trees cultivated in Cevlon do not 
reach this standard, but depart from it in different 
ways. Hevea contains very pure latex, but its 
laticiferous vessels do not seem to communicate 
freely, so that a large number of incisions are 
needed to get all the milk; Castilloa has much 
freer communication, but a more impure latex, 
and less percentage of caoutchouc therein; 
