140
THE ESSEX NATURALIST.
As regards the uncertainty which exists as to how far the
study of aquatic organisms can be claimed as coming within the
province of Field Club activities there are evidently two questions
to be considered. The first is whether all the organisms occurring
in water can be regarded, from any point of view, as being legiti-
mate objects of study, and if not where the line is to be drawn.
The second question is whether, of the organisms admitted, all
or only certain sections of knowledge about them are to be re-
garded as consistent with Field Club work.
So far as the first question is concerned no doubt everyone
will agree that all the larger aquatic plants and animals must
be admitted as objects claiming the attention of field naturalists.
It is with respect to the organisms on the border-line between
macroscopic and microscopic and to the microscopic organisms
themselves that doubt appears to exist in the minds of many.
I should imagine, however, that if the matter is given a little-
consideration, there will be very general agreement to the
inclusion of those smaller organisms which require no more than
the use of a pocket lens for their approximate determination in
the field. This in fact is conceding only what is freely allowed
in the case of terrestrial plants and animals. But, presuming
a line could be drawn somewhere, which, however, in practice
would be very difficult, since it would separate several natural
groups arbitrarily into two parts, what of the essentially micro-
scopic forms which cannot possibly be determined without the
aid of a microscope ? Are they also to be included or not ?
My own opinion is that, for certain purposes at any rate, they
must be included, and for the following reasons. In the first
place the collecting of aquatic organisms, however small their
size, is "field" work of the most obvious character. Secondly,
if the microscope is to be used at all in connection with Field
Club work, as indeed it must be for the proper identification of
some at least of many kinds of land organisms (e.g. lichens, mosses,
fungi, mites, the smaller insects, etc.), there seems no logical
reason for limiting its use to any kind of aquatic organisms.
Further, it should surely be one of the ideals of every Field
Club or local Natural History Society to get together materials
for a complete census of the flora and fauna of its own province,
and this of course cannot be done if the microscopic forms are
ignored. Then, as we shall see presently, there are a number of