May 1, 1899.] THE TROPICAL 
AGRICULTURIST. 
771 
PEARLS: NATURAL AND ARTIFICIAL. 
M. Dastre contributes to tlie first February num- 
ber of the Revue dcs Deux MomJes n \ery intei'- 
estiug paper on the production of line pearls botli 
by natural and artificial means. 
We liave lately been interested in the announce- 
ment that a syndicate in London were placing 
upon the mai'ket consideraljle quantities of pigeon- 
blood rubies \^"hich were products of the labora- 
tory and not of the mine, and now it seems that 
as far back as last November the French Academy 
of Sciences received a report on the experiments 
of a M. Boutan in making artificial pearls. The 
curious part of it is that in spite of the advances 
made in biology we are still ignorant of the precise 
manner in which the natural pearl is produced 
inside the oyster, and our imitations of nature must 
therefore be empirical and consequently not always 
trustworthy. There is no need to follow M. Dastre 
in his investigations into the ancient repute of 
the pearl as a gem, It is enough to say that the 
principal fisheries of pearls are those of Ceylon, 
tlie Coromandel Coast, those whicli have existed 
from time immemorial in the Persian Gulf, and 
those of the Red Sea, the Antilles, and Australia. 
M. Dastre contrasts the intelligence of the Indian 
Government, which carefully regulates the fisheries 
\\ ithin its control and draws from them an im- 
portant revenue, with tlie entire neglect by France 
of her fisheries in the Gambler and the Tuamotu 
Islands. 
It is interesting to note that M. Dastre does 
not expect much danger to the market value of 
the natural pearl from the competition of the arti- 
ficial one. The artificial cultivation of the pearl 
oyster appears to be a matter of considerable diffi- 
culty, which is always likely to handicap the artifi- 
cial pearl in competition with the spoils of the pearl 
divers. By artificial pearl is meant, of course, 
some foi'eign body introduced into the oyster and 
clothed by it in the course of years with the mother- 
of-pearl covering with which the creatui-e also 
covers its shell. The objection to introducing this 
foreign body into the oyster is that the result is not 
so fine as the pearls which are produced by natural 
means by the oyster itself. Curiously enough, jn the 
last century a Swedish naturalist attempted to pro- 
duce the real article by irritating the oyster, but 
though a merchant of Gothenburg bought his 
scheme for a lai'ge sum, he seems never to have 
carried it out. The Chinese, who .are not cele- 
brated as a nation for humanity, introduce into 
the unfortunate oyster all kinds of irregularly 
shaped foreign bodies, sucli as little dragons and 
idols, whicli must irritate the creature much more 
than a pei'fectly rounded object. As for the ex- 
periments of M. Boutan, their object was appa- 
rently not commercial but scientific. In conclu- 
sion, M. Dastre gives some interesting figures as 
to the value of famous pearls. It seems that the 
modern collections of pearls do not really rival 
the magnificence of those piossessed by the wives 
of famous Romans, and nothing, M. Dastre thinks, 
could compare with the magnificence of one neck- 
lace possessed by LoUia I'aulina. 
CACAO PODS' DISEASE. 
Tho following Report from scientific men 
ill Trinidad will bo of interest to cacao planters 
in Ceykni. It shonki be carefully compared 
l)y them with the Report of Mr. Carruthers 
oil the same subject as they will find it 
reproduced in their file of the Truplriil 
A(jri,rulhn-isl. It will he ohserved that the 
Trinidad investigators make light of cacao 
disease and genei'ally blame ]\lr. Carruthers 
for giving it undue importance ! This is simply 
absurd ; for, the fungus in Ceylon had done 
most serious damage in cei'tain districts and 
among the weaker cacao; but prol)ably 
Messrs. Marryat, Carmody and Hai-t merely 
mean that undue importance has been given 
to the cacao [jod disease ? 
EE-PORT OF THE CACAO COMMITTEE ON 
"CACAO POD DISEASE." 
(Laid before the AgriouUnral Society, Trinidad, I'lth 
Maich, 1899.) 
At the meeting of the 14th February after discussion 
on the so-called " Cacao pod disease, ' the Committeo 
appoiated a Snb-Goinniittee to make a Report, dealing 
with the various facts brought out in the discussion, 
and to invite further information from members of the 
Society. 
The opinion of tho Sub-Oomraittee is as follows : — 
1. That the malady is due to a fungus, the precise 
species of whicii is beiug iEvestigated at Kew, bat 
that pending a longer term of observation and of a 
series of experiments, it would be premature to make 
too positive assertions, as to its origin and growth. 2. 
Experienced planters state that they have in certain 
se isons, known the pods lo be similarly affected any 
time during the past 25 years. Much depends on tlie 
nature of the soil. November and December are the 
worst months?, especially if cold, wet, and a northerly 
wind follow a hot Indian summer. With the dry 
weather the fungus disappears, 'd. There is no evi- 
dence to show that the Cacao tree itself is in any way 
affdcled by the malady of the pods and to all nppearance 
a pel fectly healthy tree may be laden with diseased 
jjods. The fuugus has not been observed to penetrate 
to ('amage the bark, even when a diseased pod is lying 
against the trunk. 4. The experiments which the Gov- 
erument Botanist has found time to make, unfortu- 
nately only on a limited scale, prove conclusively : — a. 
That a sound pod inoculated from a diseased pod, 
readily takes the malady and becomes rotten in a week 
to ten days. i. That pods in the immediate neighbour- 
hood of the inoculated pods, though purposely wounded 
with a knife, were not affected. It has yet to be proved 
that the malady is infectious. 5. It having been shown 
that a wounded pod readily accepts inoculation, 
it is obvious that the fungus may be carried 
and spread by rats, bats, squirrels, wood-peckers, 
insects, etc., which attack the pod. 
0. Assuming this to be possible, the origin and 
the home of the malady may not be far to seek. The 
Government Botanist in visiting an estate by request, 
noticed within a narrow radius of the "breaking" 
grounds, a greater number of black pods, than in 
other parts of the cultivation. 
7. In some cacao countries (Surinam and Central 
America), the practice of breaking the pods in the 
field itself, 'Uid of allowing the shells and refuse to 
remain and rot on the ground as in Trinadad, is un- 
heard of. The pods are picked and carted to the 
" works," then broken, and the refuse placed on the 
ma.nure heap and properly treated. To ask the 
planter in the hilly districts to adopt this system, 
would be too great a tax on the labour and stock 
at his disposal, but pending further investigation, 
and as a matter of precaution, it is recommended 
that the following procedure be adopted : — (1) Where 
burning is not practicable, to cover all refuse 
with soil and bury it, or otherwise coinplefchi destroy 
it. (2.) Or the " broken " pods may be chopped up 
small and covered with quick or temper lime. This 
in time would form a safe and valuable manure, 
(ii.) All pods showing signs of attack should be 
carefully collected and destroyed. The probable home 
and nursing ground of the fungus would thus be 
destroyed. 
8. In conclusion the Sub-Committee is inclined to 
think that an undue importance has been attached 
in certain quarteiv to the question of disease amongst 
Cacao, which would never have arisen but for the 
publication of Mr. Carruthers' Report on Ceylou 
cac'io disease. 
Complaints of the same character luwe 
arisen in Trinidad from time to tinic for many 
years past, but so far as can bo aaccrCained 
no serious loss has occtirred ; but the question having 
