312
THE SEAS
are left in this water for one day.
They quickly open their
-
shells and discharge the contents of their stomachs including
any bacteria they may contain, while at the same time
_
they take in sterilized water.
This water is then run off
and the tank lled with fresh sterilized water for a similar
.
period to make sure that the mussels are thoroughly
cleansed internally.
Again the water is run off and, last
of all, the shells are sterilized with chlorinated water, the
cleansed mussels being then packed in sterilized bags and
.
to the markets.
This system of cleansing was
began on a commercial scale in 1916, and has proved a
complete success, the avour of the mussels is not impaired
while there have been no further complaints of pollution,
_
and the mussel shery has regained its original importance;
As expenses have to be met by a xed charge for each bag
of mussels cleansed,‘ only the larger mussel sheries can be
treated in this way owing to the expense of erecting the
cleansing tanks, - and consequ‘ently many of '
the smaller
,
sheries which have been condemned cannot be treated
in this way, but a second cleansing'station has recently
been erected'at Lympstone on the River Exe in Devon'
shire.
Mussels
are
only collected » during the winter,
and
during the summer months the tanks are used
for experiments on the purication and breedi_ng of
oysters.
_
'_
.
.
—
Oysters do not take in bacteria quite so readily as do
'
mussels, but when they are polluted are more difcult to , -
purify, owmg to the fact that unless the water is over a
'
certain temperature they refuse to -opentheir shells and
so
become sterilizedIt is‘ probably only a'
question of time before a
of purication
_
is devised when it will be possible with
safety to
'
eat oysters_ from .many localities now banned on account
of
.
pollution. … The shellsh industries are in their infancy