NOTES ON THE FOOD OF OYSTERS IN ESSEX. 169
If, in years gone by, I had anticipated that I should ever
write such a paper as this, I should nave prepared a correct list
of everything I found. I feel that what I have now done in
these notes is very incomplete, and that I have seen many forms
which I cannot remember, since they did not seem of particular
interest for my own special purposes, or because I can obtain
them so much better in other localities.
NOTES ON THE FOOD OF OYSTERS IN
ESSEX.
By H. C. SORBY, LL.D., F.R.S., F.L.S., &c.
[Read September 9th, 1897.]
SOME years ago I was led to think that very much remained
to be discovered with regard to the food of oysters in different
localities. No reliance can of course be placed on the exami-
nation of the contents of the stomach after the oysters have been
kept for some hours out of the natural water, since the food
would be digested ; and the sooner they are examined the better.
When lying in the yacht at Paglesham, I had a good opportunity
for studying this question, since my friend Mr. James Wiseman
gave orders to his men to supply, me with oysters, which were
brought to me and the contents of the stomach examined with a
microscope, only a few minutes after having been taken out of
the water, so that some of the Diatoms they had eaten were still
alive. I found that at Paglesham the chief, if not the entire,
food was Diatoms. Soon afterwards I had the opportunity of
observing oysters taken out of Brightlingsea Creek, and which
were examined as soon as I could, but not so immediately as in
the case of those at Paglesham. I was surprised to find that
the food of the Brightlingsea oysters was very different. Diatoms
were few in number, or absent, but on the contrary, the
stomachs contained many small animals, which I took to be
Infusoria, or small larvae, not easily identified. At all events the
contrast in these two cases was so great as to readily explain
why the growth and flavour of oysters fed in different waters
may be so different. Since then my attention has been
directed to other matters, and in any case I could carry out this
work only in an intermittent manner, but I most strongly com-
mend the study to anyone who has the needful facilities, and who
could examine the oysters of different localities fresh from the
water at every season of the year. It seems to me that by this
means much valuable information might be learned.