22 
THE TK©PICAL AURICULTURIST. [July 1, 1902. 
dates from ths days when the earth was young, and 
when its carbon became crystallised under the action 
of fervent heat. For, as most of my readers may know, 
the diamond simply represents crystalline carbon. It 
has Ufear rehition^, chemiciilly speakiug, in biacklead 
and charcoal. Ohemical science, recognising this fact, 
h«s attempted to produce diamonds from a carbon 
basie. In this imitation of u.iture I believe they 
hav« proved successful ; only the diamonds, built up 
as it were from their carbon parentage, are so small 
that, commercially speaking, tliey are of no account. 
Till chemistry can imiuite on a bigger scale than 
is possible today the work of the inner fires of the 
globe, it is hardly possible to conceive of the diamond 
being successfally imitated by the laboratory product. 
The ruby .md the sapphire also represent niinBCal 
products which possess a geological signiflcance. But 
it is entirely different in the case of the pearl. There 
w« hare to deal with the manufacture of an animal 
form, which of course belongs to the molluscan or 
Bhellfish type of life. If wo examine an oyster--heU 
we find it to be lined with a beautifully delicate layer 
known as nacre or mothnr-of-psarl. In the well- 
known "ear-shells" this layer assumes great thickness 
a:id by refr icting the light from iis ridge< gives us a 
tvpicvl play oi colour and of iridescent hues. 
Every mollnac in fact shows mother-of-pearl 
jvs the lining layer of the shell, although as may well 
be nndevstood there are infinite variations in respect 
of the quality, delicacy, and therefore commercial 
valne of this substance, in many shells it is coarse, as 
to others it is of fine texture and special colour. It is in 
the latter case that it gives origin to the pearls of 
great price. 
The typical peoil producing mollusc is, of course, the 
pearl oyster concerning the welfare of which 
BD English Commission is at present busily inquiring 
in Ceylon. The Scottish pearl mussel wos aleo cele- 
brated in its day. I use the past tense here because 
the goose that laid the golden eggs was daily killed in 
this case as in so many others through the mussels being 
fished to extinction in the rivers of the North. These 
shellfish, as the typical pearl-producers, present us 
therefore with an illustration of the animal manu- 
facture of a precious product. _ Certain interesting 
circumstances connected with pearl-production have of 
late been ventilated by Dr U L Jameson in the course 
of a paper read by him before the Zoological Society 
of London. What Ur Jameson hai to tell us of the 
manner in which pearls arc produced in a certain 
■pecies of mussel serves to throw light on the possible 
manner in which they are manufactured by other 
ihellfibh. 
Each oyster or other shellfish is enclosed in a kind of 
ikin to which naturalists giva the name of the 
" mantle." it is this membrane which at once 
envelops and encloses tlie body of the animal and of 
course lines the shell. The mantle is the source of the 
mother-of-pearl which is deposited by it in the shell 
and naturally it is to the mantle that we also look for 
formation of pearls. Long ago it was known that each 
pearl was formed round some solid particle or other 
which had gained a'imittance to the shell. It was as 
if the irritation of tke particle induced the mantle to 
lecrete around it layers of the mother-of-pearl 
anbslnnc* by way of rendering the foreign body 
harmlesi. In the case of the pearl-producing molluscs 
the real jewel was thus formed while in others the 
" Pearls " were of course valueless. The Chinese have 
been nccustomed to introduce into the shells of big 
molluscs little metal images, which become coated 
OTcr with the pearl secretion and are thus rendered 
presumably more attractive. So that scientista 
aeaert that the pearl is really in one sense 
an abnormal thing, in that it represents the physio- 
logical resentment of the shellfish against a particle 
which has no business to be where it is. 
Dr Jameson's discovery in thie light is of a singular- 
ly intereatiog nature. For ho tells us that the nuoleu3 
or particle, around which a pearl ia formed in most 
jftsee, ia (be larva or yonog form oi a c«rUiQ praaitv 
which has found its way into the shell. The parasite 
is a fluke, and is therefore allied in its nature to the 
animals of that name which we find familiarly infesting 
the liver of the sheep and the ox. The flukes whose 
youthful forms gain access to the shells of the mol- 
luscs a) a found as unbidden guests ia the eider duck 
and in the Scoter duck. The life history of the parasites,, 
as far as we kuow it, shows us that on escaping from 
the egg the young forms seek the water. Then they 
require to pass into the body of another animal than 
that in which they become mature in order to undergo 
the preliminary stages of their development. In the 
case of the sheep-flnke, we know that it passe.3 the 
days of its youth in the body of the water-snail ; and 
so in the case of the flukes Dr Jameson describes we 
may suppose their young select the mussels as their 
temporary hosts. 
It is when the young flake in the shell comes to 
grief, and its body degenerates into a limy speck, 
that it forms the nucleus of the peail; but occasionally 
it will boieits way out of the pearl and thus leave the 
latter presumably imperfect. Dr Jameson has 
succeeded in infecting mussels artificially by keeping 
them in an aquarium. He also suggests that the 
real pearls of the oyster similarly originate from the 
young of the parasites which lodge within the shell- 
fish. If infection of the pearl oyster could be rendered 
possible and swarms of parasites could be liberated in 
an oyster-bed doubtless the artificial production of the 
precious stones would become a feature of commerce. 
But it seems to me that, just as the diamond is only 
carbon after all, so our beautiful pearls parallel its 
case by owing their origin to the work of a. low form 
of parasitic life. 
THE TEA TRADE WITH PERSIA. 
In your issue of the 1st instant, under the above 
heading, appears an extract from an otBcial com- 
munication from Meshed, suggesting that the 
Indian Tea Association should, for a time, turn 
their attention towards the Bombay Agents of 
Persian firiiis, who might be won over to the ad- 
vantage of buying tea at some place nearer the 
producing tea gardens than Bombay, and of the 
land ront;e as against the sea route. As an old 
resident of Teheran, I have watched with interesi 
the various proposals made and the action taken 
by the Indian Tea Association in the matter. The 
Nushki-Seistan route is being boomed to an extenk 
which it certainly does not deserve, for what 
leasou 1 am at a loss to understand. Those 
interested in tlie tea trade with Persia, should, 
in my opinion, use their utmost endeavours to 
popularise Indian tea in such parts of Persia as are 
already to an extent supplied with Indian tea, 
and where British influence ia in the ascendant ; 
they should not commence operations in sucli parts 
of the country as are solely under Russia's influence, 
and where iiecessaiiiy the markets have already 
been captured by Russia to a certain extent, 
First as.sault and capture the outer works, before 
trying to take the enemy's stronghold. It is not 
much use trying to win over the Bombay Agents 
of Persian firms, where, no doubt, vested interests 
would l)e at stake. The best plan by far would 
be to send out an agent with a supply of tea to 
travel through the country to be exploited, and 
to cultivate the already established taste for such 
teas. When this is accomplished, the Bombay 
Agents would of (lecessity be obliged to buy such 
teas to meet the demand which would ari.se. 
The towns in Persia I would ad vocate an agent 
visiting are Bushire, Shiraz, Kerman, Ispahan, Yezd 
Teheran, Kermanshali and Haniadan— all grea* 
ooDiniercial centres. Th« less said the better ftboajj 
