\00 THE TEOPICAL 
Dublin (since F.R.S., and Professoi' of Cam- 
bridge University) who wrote of " yaville- 
Kent " as an able man and that be was 
going on a special mission to North- West 
Australia, to study the Fisheries there. 
What further Reports Mr. Saviile-Kent 
has published, we do not know ; but enquiry 
ought to be made of both the Queensland and 
West Australian Governments as the owners 
of Pearl fShell ;ts well as Pearl Fisheries. 
Then we have also dug out of our collections, 
a " Report upon the Pearl Fishery of the Gulf 
of California by Charles Townsend" — illustra- 
ted with photographs ; and a " Report upon 
certain Investigations relating to the Planting 
of Oysters in >Southern California, by Charles 
H. Gibbert," also with plates — both Reports 
being dated 1891 and addressed to the Washing- 
ton authorities. Most probably the investi- 
gation was continued and further Reports 
olio wed, and perhaps, from California, Sir VVni. 
Twynarn might learn of Pearl Oysters being 
artificially cultivated. But, in any case, we 
think Mr. Coliett and ourselves have said 
enough to show that the Ceylon Government 
should take action— and it Professor Herd- 
man were consulted, he could probably lay 
bis hands on all the literature on the subject 
from America, Australia and India (and pos- 
sibly referring to Chinese experiments with 
Pearl Oysters) before giving his opinion as 
to what could be done by Science in connec- 
tion with the Ceylon Pearl Fisheries. 
OUR PEARL FISHERIES. . 
A PLEA EOK SCIENTIFIC INVESTIGATION. 
m 
Watawala, July 1. 
Dear Sir, — After reading your recent editorial 
remarks (sue above) upon SirvViliiam I'wynani's Re- 
port on (lur Pearl iislieiies, and after a perusal of 
that vaiuabie and elaborate account, tbe question is 
naturally forced upon one : Is it not passing strange 
that we still remain, after more than a hundred 
years of occupation of the island, in almost com- 
plete ignorance of the habits and instincts of the 
pearl-bearing nuissels of the Guif of Mannar? 
The paramount importance of the question be- 
comes evident when we remember that the total 
revenue derived from the Pearl Fisheries since 
1796, amounts to no less than one million pounds 
sterling; and this in spite of the fact that some of 
the most promising of our fisheries were spoiled 
by the remarkable, and, so far altogether unac- 
counted for, disappearance of the " oysters," just 
as they were about to arrive at niaturrty. 
The fact that the two oldest authorities upon our 
Pearl Eisheries (Sir W Twynarn and Captain 
Dounan) hold diverse opinions regarding the prob- 
able cause or causes of these disappearances, 
shews how very much there is yet to be learned of 
the whole subject. 
To the zoologist, it is at once clear that this and 
other vexed questions can only be set at rest by a 
tlioroujjh and systematic investigation into the 
Natural tlistoiy and Life Conditions of the Pearl 
OysLcr — more particularly in its early and post- 
la.rval stat;es. 
At present we are without any reliable data or 
at< iu'iu,e information upon tliose points ; and it is 
not nnpos!-;ible that it may be found tliat there 
are many agencies alfecting the health and well- 
lieing of the pearl-oyster which may be brought, 
in a greater or l(;ss degree, beneath artilicial 
coulrol. 
AGRICULTURIST. [Auft. 1, 1900, 
The fev/ attempts at systematic investigation 
that have been made, appear lo have been aban- 
doned before any real knowledge of the s^ubject 
had been gaineil. The labours of Dr. Ke aart 
(1857-9), which gave promise of the best results, 
were unfortunately brought to an end by his 
.sadden death ; and the employment of Mr. 
Holds'.vorth by Government in 1864 for a period 
of five years, appears to have led to no increase 
in our knowledge of the subject : for the simple 
reason that his energies were never properly ap- 
plied. Sir VV Twyman tells us that "he did not 
see a fishery, and did not witness an inspection of 
a batik with a bed of oysters on It, young or old." 
He also points out that " as the supposed teim of 
a Pearl-oyster's existence is seven year.*, a 
Naturalist would not be able in five years to 
complete his jesear&lies and he in a position to lay 
anything definite before Government." And, 
finally, Sir William says : '' No Naturalist has yet, 
so far as I am aware, reared Pearl-oysters in an 
aquarium, tank, reservoir, or enclosed portion of 
tlie sea from minute spat to maturity, ascectain- 
ing their exact condition at various stages of 
growth." 
Rut wliile we in Ceylon have been content to 
remain in ignorance, the study of Marine 
Zoology in other parts of the world has 
during the last quarter of a century, made 
remarkable progres.«. The return home of the 
" Challenger " expedition in 1874 gave an impetn« 
to the invsstitiatioii of this important branch of 
natural science which has already led to valuable 
results. Marine Biological Stations have been 
established in different parts of Europe and 
America, which have greatly facilitated methods 
of research. The life-liistory of a number of our 
principal food-fiahes has been worked out, and 
we are now familiar with many of the conditions 
of life in the sea wliich were formerly quite 
unknown. 
For instance, it has been ascertained that 
marine life is, in many respects, almost as localized 
as that of the land ; and that certain groups of 
plants and animals are characteristic of particular 
areas. We also now know that certain depths 
of the ocean contain organisms which are only 
to he met with in their own particular water 
strata — in accordance with what is known as the 
law of bathymetrical distribution. 
Again, it has been discovered that almost all 
marine animals and plants are extremely sensitive 
to variations in the temperature, and in the 
specific gravity, and salinity, of the medium in 
which they live. These facts make it at . once 
evident that all of these conditions must be 
observed and recorded before any attempt at 
artificial propagation, or cultivation, in any par- 
ticular locality, can be expected to be successful. 
No planter would attempt lo j^row tea in Jaffna, 
or coconuts in Nuwara E iya ; and, arguing by 
analogy, it is possible — nay, probable— that the 
marine life of our shores will be found to vary 
with every increase in the depth of the water, 
in precisely the same way that our land fauna 
and flora are modified by every change in the 
elevation of the land ; climao" in Ceylon being 
almost entirely determined by altitude. 
Now, the Mollusca are — perhaps more than any 
other class of animals — greatly influenced by their 
environment. Take the land-shells for example. 
Their distribution is so local that an experienced 
collector can at once name the locality in which 
any particular .species is likely to be foiuid. la 
