THE TROPICAL AGRICULTURIST. 
[March 1, 1902. 
of tho HeMnameeba parasite. If lett in undistur. 
bed possession, tliey will pass lluougli a sexual 
cycle in the blood of the nianj reproducing tlieni- 
Belves by fission, i.e., by the breaking up of the 
mature parasite into a number of spore-like bodies, 
•which will themselves grow to their full size and 
break up in like manner. Without further inter- 
ference the disease will be confined to that one 
person. But if a certain kind of mosquito (of the 
genus Anopheles) bites the patient and imbibes 
his infected blood, the contained parasites under£;o 
a new development in the body of the insect,— a 
true sexual cycle,— the parasites becoming differ- 
entiated into male and female orjianisms repro- 
ducing young ones in a normal sexual manner. 
These young parasites find their way through the 
tissues of the body of the mosquito and congre- 
gate in enormous numbers in the glands at the 
base of its proboscis. Then, should that mosquito 
bite another person, the parasites are injected 
into his blood, and once more go through iheir 
sexual cycle, the periods of their maturity and 
reproduction corresponding with the periods of the 
induced fever. We thus see that the mosquito 
acts as an alternate host tor the parasite. And so 
the round continues— man — mosquito— man— mos- 
quito— man, in a continuous aeries. 
The " Structure and Habits of Mosquitoes" 
are next described. About ten genera of the 
family culicidoj are known in Ceylon, Culex 
and Anopheles are fully described and dis- 
tinguished and their habits and haunts 
make a most interesting study. Then comes 
the question " How to avoid and get rid of 
mosquitoes." Preventive Measures, he divides 
into thre* sections : — 
Firstly.— Those aimed at the extermination of 
the mosquito. 
Secondly.— Those designed for the elimination of 
the malarial element. 
Thirdly.— Protection from the bites of the mos* 
quitoes. 
Live or sleep under mosquito curtains 
where feasible. Allow no standing water 
anywhere, and on water huts or tanks, a thin 
film of kerosine is very destructive to the 
larvse. These are the broad directions, but 
Mr. Green gives many hints and explanations 
upon the value of familiar remedies such as 
the free use of castor oil leaves and sundry 
essential oUs; fumigation with sulphur, the 
use of white stockings and coverings. Thus, 
small doses of sulphur, taken internally ren- 
der one unpalatable to the mosquito. And 
as to cures for the irritation of the bite it 
is suggested to moisten and rub soap on the 
■pot. For the treatment of malarial fever 
when a doctor is not available, Mr. Green 
quotes Dr. Patrick Manson's advice, and 
with this we close :— 
••During a paroxysm of ordinary intermittent fever 
it is better, before giving quinine, to wait until 
the rigor and hot stages are over and the patient 
is beginning to perspire. A fever fit once hegun, 
cannot be cut short by quinine, and to give 
quinine during the early stages aggravates the 
headache and general distress ; bat so soon as the 
skin is moist and the temperature begins to fall, 
the sooner the drug is commenced tiie better. 
Ten grains, preferably in solution, should be ad- 
ministered at the commencement of sweating, and 
thereafter five grains every six or eight hours for 
the next two or three days. This is almost a 
eertftln onr«," 
The great value of this brief compact cir- 
cular can only be understood after a care- 
ful perusal. Already it is widely appreciated 
throughout the Northern Province ;ii recent 
traveller down the road heard it re- 
ferred to at several stations in terms of 
high praise both for its practical usefulness 
and for the popular treatment of the sub- 
ject. 
♦ 
TRINIDAD PRODUCTS. 
Governor Sir A. Moloney's annual report ou Trini- 
dad and Tobago gives some interestiDg details as 
to the chief products of that Colony — cacao, sugar 
and asphalt. 
Cacao, — The area under cacao is nearly twice that 
nnder sugar, and is extending daily. The crop of 
1900 exceed that of the previous year by 1,100,000 
pounds, partly due to extended cultivation and partly 
to a favourable season, but the average prices ob- 
tained were about 5s per cwt lower, viz., 68s to 759. 
It paid to ship cacao when, in 1896, the prices had 
fallen to 45s, and the cost of production, apart 
from rent and interebt on capital, is generally esti- 
mated at not more than 27s a cwt. Tnough the world's 
production of cocoa is being greatly extended, ite 
consumption is increasing rapidly. 
Sugar.— Owing to dry weather the sugar crop of 1900 
was a very bad one, and had a shortage of twelve thou- 
fiand tons. Leaving out of account capital and depreci- 
ation charges, it is possible that £1 a ton profit was 
made on the sale of yellow sugars in the London 
market. On the other hand, the grey sugars shipped 
to America were probably sold at an average loss of 
two shillings a ton on the cost of production. Lasl 
year's crop (1901) was above the average, and although 
the cost of production was reduced considerably below 
that of the previous year, low prices and heavy im- 
ports into the United Kingdom of Continental sugar 
in anticipation of the new import duty more than 
neutralized the advantage. 
EuBBEE. — Rubber is the only new cultivation likely 
to provide a staple export in Ihe future. It is aa 
yet, however, in an experimental stage. There are 
some eight plantations in Trinidad and two in Tobago. 
Several large sales of Crown Land in Trinidad have 
recently been made on the understanding that they are 
to be devoted to this cultivation. It is also extending 
yearly in Tobago, chiefly in combination with cacao. 
The rubber chiefly pUnted is the Central American 
Castilloa Elastica, of which there are U'0,000 trees 
planted in Tobago, as well as some thousands of 
the Brazilian " Mouchet.'- The former ]iroaiises to be 
the most profitable. The West African silk rubber 
has al.-o been recently introduced, and its importei s are 
hopeful of its success. The greater part ot the planta- 
tions are still quite young — from one to four years old 
— and no large return can be anticipated until they 
have been seven or eight years in existence. The 
quality appears to be good. A sample of Castilloa 
grown and prepared on this Richmond estate was 
valued in England by experts at 3s 6d per lb. — Chamber 
of Commerce Journal for January. 
PEARL SHELLING IN QUEENSLAND. 
There can be little doubt according to the an- 
nual report of the British Marine Department, 
that the pearl shelling industry of Torres -Straits 
has reached a critical stage, and unless some pre- 
cautions are taken, all the shelling grounds wiihin 
a distaiice to be reached from "Thursday Island 
will have been woiked down to a payable limit, 
and the fishery will be practically closed down. 
Shelling has been carried on in Torres Straits f»r 
31 years, 
