Dec. 1, 1900.] THE TROPICAL AGRICULTURIST. 
391 
under the inspection and control of specially ap- 
pointed officers, the sj'steiu which was formerly 
in vogue of renting the pearl banks having been 
entirely discontinued since the year 1837. 
There appears to have always been a consider- 
able amount of uncertainty in respect of the 
amount of revenue derivable from this industry. 
Writing in 1697 for the instruction of the Political 
Council of Jaffnapatam, the then Commandant of 
that town justly remarked tliat "the pearl fishery 
is an extraordinary source of revenue on which no 
reliance can be placed as it depends on various 
contingencies which may ruin the banks or spoil 
the oysters." This statement holds good after a 
lapse of more than two centuries — indeed, the 
periodical disappearance of oysters from certain of 
the banks sometimes for many years at a time, 
may be said to form one of the peculiar charac- 
teristics of the Ceylon fishery. 
Nevertheless, since the British occupation of the 
Island a sum equal to more than one million 
sterling has been derived from the fishery ; and the 
mat ter is therefore one of immense importance to 
to the Government of the Colony. 
Conservation of Pearl Oysters. 
The question as to whether any means can be 
adopted to conserve the oysters upon the beds and 
thus to place the industry upon a more stable and 
permanent footing, must in the first instance de- 
pend upon a knowledge of the physical and biolo- 
gical conditions ruling upon the different banks. 
There are reasons for supposing that these con- 
ditions undergo frequent change ; but the cause, or 
causes, thereof have yet to be definitely ascertained. 
It is well-known that the northern and western 
coasts of Ceylon are being vtfradually uplifted 
from the sea. On this account* it is possible that 
an increasing amount of saud — which is very in- 
jurious to all bivalve molluscs— is finding its way 
from the northern rivers into the waters of the 
gulf.t It may also be that changes in the tempe- 
rature, and in the degree of salinity of the water, 
have the effect of rendering certain of the banks 
untenable to the oysters for more or less prolonged 
periods. Further, it is stated upon good authority 
that the strong ocean currents from the Bay of 
Bengal, which sweep round the coasts of Ceylon 
and Southern India, contribute largely to the 
causes which denude the oyster banks. Altogether, 
it will be seen that this question is one of some 
difficulty, and thfit it must involve the solution of 
quite a number of local marine problems. 
On the western coast of South America, which 
is likewise at present being upraised from the sea, X 
pearl fisheries formerly existed which gave rise to 
wealthy and populous cities — "whose very ruins 
have now perished." Yet, doubtless some day 
Science will provide means for the revival of these 
industries possibly — as in the case of the fisheries 
of California — by the introduction of special 
divine apparatus ; for after all it may be found 
that the oysters have merely migrated seawards in- 
to deeper and more sheltered waters. 
* Mr. Boake, in his Monograph of Mannar (1888)" 
tells ua that a pearl bank at one time existed on the 
north of that island ; and according to ancient Sinha- 
lese records, there were formerly pearl banks in the 
vicinity of Mount Lavinia. It is significant that of the 
8.5 pearl backs in the Gulf of Mannar, viz.. 19 on the 
Oeylon coast and 66 on the Indian, only two the 
Cheval and Modragam banks, are now profitable. 
t "Man-ar" is Tamil for "sandy river." 
t Darwin, " Naturalist's Voyage in the 'Beagle.' " 
In regaru to the question of artificial cultivation 
&nd conservation it is important to observe that 
the pearl oyster — like the Strassburg goose only 
becomes of special commercial value when it has 
developed certain conditions of organic disease. We 
have already seen that pearls must be regarded as 
a pathological product, and we find this conclusion 
well supported in the records of the fisheries. 
These contain frequent references to the number 
of pearls found in diseased and dying Oysters ; and 
experienced divers are apparently agreed that the 
probability of finding pearls is always greater 
when the oysters are crowded together, and lae- 
come humped and distorted in shape;* and at the 
same time afiordcoverfor all kinds of marine worms 
and parasitic creatures. Thus unhealthy conditions 
of living must presumably be encouraged in order 
to promote the diseases which lead to the formation 
of pearls. In the course of an address to the 
Malacological Society of London, in 1896, Profes- 
sor Howes, referring totne peculiar characteristics 
of certain marine mollusca (chitons) remarked : 
"In its bearings on the conditions of local distri- 
bution in shallow water, on bathyniQtric extension, 
and specific variation as related to these influences, 
the experimental method appears to me to give 
promise of most important results in Malacology. 
Just as the physiological graduates off into the 
pathological, the full significance of many a 
healthy or a diseased state becoming intelligible 
only on a knowledge of its opposite, so, in the 
hands of the experimentalist, the normal 
phenomena of animal life will most assuredly in 
course of time become illumined by prolonged and 
careful study of the organism under changed con- 
ditions. And from all that is now going forward 
it is plain that the pathologist holds the key to 
many a life problem." 
The Chairman then called upon Capt. Donnan 
to offer remarks on the subject. Ca >t. Donnan 
spoke as follows:— 
Capt. Donnan's Remarks. 
In regard to the remarks upon the similarity of 
the Gulf of Manaar Pearl Oysters to those of the 
Persian Gulf, and the* suggestion that the former 
is comparatively rare in the Arabian Seas, I will 
relate how I came to ascertain that the Gulf of 
Mannar oyster is found in great abundance in the 
Persian Gulf. When I went to England in 1875 
I took witii me a small sample of Ceylon Pearl 
Oyster shells to ascertain if they were of any com- 
mercial value, and during my visit to London, 
I went into the office in Mincing Lane of Messrs'. 
Brooks & Faith, Produce Brokers, saw the head 
of the firm, and asked him if my sample of oyster 
shells was of any commercial value. He looked at 
them and said "these are what we call Lingas 
from the Persian Gulf." I replied, " that they came 
from Ceylon." He said, "don't tell me that, I know 
better," and pointing to a shelf on which there were 
a large number of oyster shells, said, " there are 
your shells, they have come from the Persian Gulf, 
and large quantities of them are sent to us regularly 
from Bombay." He then examined my sample and 
said, " You have been polishing them up, and if you 
had not done so, they would have been worth thirty 
shillings per cwt." I replied that the only polish- 
ing they had was that of being exposed to the sun 
and rain on the beach at Sillavaturai for twe.ve 
months. 
* These small thick oysters are called by the people 
"Koddai-pakku," via. "arecanut oysters" (Twynftna'" 
Report, p. 59). 
