The Milan exchange. (Milan, Gibson County, Tenn.) 1874-1978, 1879-09-18
Interesting Experiments with Oyster
Eggs.

Prof. Brooks of John Hopkins Univer-
sitv has been recently engaged in ex-
periments with the object of securing
the artificial propagation of oysters, and
on the 29th of May his efforts culminat-
ed in success. Before these experiments
naturalists were not fully conversant
with the early history of this mollusk's
development. A correspondent of the
Baltimore Sun, who witnessed the
process of making embryonic oysters,
says in his account of it: ''Half dozen
on the half shell served on plate, a few
watch crystals, small glass jar, little
water and the microscope constituted
the laboratory. The oysters had been
taken fresh from their beds and opened
carefully. In this way they will live for
day or two if kept in cool place, and
all the while the heart may be seen to
pulsate in its cleft near to the muscles.
Close to the heart lay what is usually
called the fat but which is really the
reproductive organs. These are wrap
ped all around the stomach, liver and
digestive organs, the latter being the
belly or dark parts of the oyster. The
flaps extending around the whole of one
side of the shell are its gills, through
which it breathes and separates its food.
The mouth is at the butt end of the
them. Male and female oysters
on the half-shell can not be told apart,
and indeed one in fifty is believed to be
hermaphfodite. 1t is claimed that oys-
tiers are females when young, and males
when they become old and larger. But
the facts have not been established with
certainty, nor is it of Importance. To
produce free swimming ciliated embryos,
the operator pinched away with tweez-
ers a particle of the generative part, put
it into watch-cTystal, and stirred it
until the eggs were well shaken out.
The water was now milky from the great
number of eggs. The microscope de-
termined the sex, which in the present
experiment proved to be male. Under
the microscope these male cells appeared
to be dots, perpetually in active motion,
and each one of them being sufficient
for impregnation when properly lodged.
The female eggs are 100000 larger than
the male cells, but are invisible to
the naked eye. Having been washed
out into separate watch-crystals, the
eggs are mixed with the male cells.
Then viewed under the microscope the
male cells are seen to attach themselves
vigorously to the egg in eager crowds,
but only one of the many is supposed to
impregnate. The first change apparent
is the disappearance of the germinal
vesicle, and this is accomplished
in a very few minutes. The
egg then becomes spherical and
remains quiet for one or two
hours, when a kneading process becomes
visible. A globule appears on the sur
face and this is the beginning of seq
mentation. Then by degrees the egg
becomes divided into smaller and small
er granules. This process Of subdivision
occupies two hours, and at the end of
this time small, transparent swimming
embryo is found, which is the oyster in
its infantile state. The whole process
occupies from four to six hours, accord
inc to the temperature, although in the
present instance it was brought to a sue
cessful issue in four hours. Professor
Brooks, in his previous experiments, had
raised oysters till they possessed the
ella, which serve to propel the micro
scOpic animal, but they died without
further revelation of the mystery of life.
In the present experiment he had the
satisfaction of developing the embryOs
until he could clearly trace their digest
i've organs, and he is inspired with the
hope that continued watchfulness will
enable him soon to see the infants begin
to assume their armor of shells. 1t is
believed that there is no specific time for
the spawning season of the oyster, and
that it continues throughout the summer
months, though this is a point not yet
definitely settled.-Scderace Neoos.