430 THE FRESH-WATER LOCHS OF SCOTLAND 
limited piece of nature with its own laws to which the organisms 
are compelled to accommodate their organisation. The great model 
is ForePs excellent monograph, Le Lknan. All these papers deal 
with the regular annual variation in temperature, the transparency 
of the water, a little in regard to environment, a list of organisms — 
never complete and only thoroughly carried out for those groups 
which most interested the author. Tn the biological parts we find 
casual remarks, but really the only remarks of scientific value. All the 
papers finish with a chapter giving the results of the investigations, 
the peculiarities of the physico-chemical conditions combined with 
the characteristics of the organic life, intended to give us a clear 
understanding of this one lake as different from other lakes. These 
chapters are almost identical in all the papers. 
\\\ my opinion, the whole of the above tendency in linniology has 
perhaps been correct and useful during its infancy ; now, I think it 
must be regarded as a stage in evolution which we have outgrown. 
If a lake has to be thoroughly explored, it is of course necessary 
to have a preliminary idea of the lake, its physico-chemical conditions, 
and its biology, but only rarely is it necessary to publish this 
material. It is just such preliminary explorations that the above 
papers represent, and beyond them the investigations of the lake 
concerned only seldom extend. 
When this preliminary exploration has been done, the more 
thoroughly scientific work should begin. We will, for example, 
suppose that the littoral region of the lake is to be explored. If so, 
there is no sense in studying all the organisms simultaneously. The 
expert limnologist will quickly find out some few species which 
ought specially to be investigated ; from the observations on the 
morphology, biology, etc., of these, carried out every fortnight for 
a year, questions will arise which can only be answered through 
investigations of the surrounding medium. This study will there- 
fore involve others, and will naturally lead to the study of the whole 
littoral region, its organisms and conditions of life. 
At present all such studies can in a very high degree be furthered 
by means of fresh-water biological stations. If we remember all 
the excellent investigations on the biology of fresh-water organisms 
(Daphnids, Apus, Trematodes, Cestodes, water-insects, Volvox, many 
phanerogams) which have been carried out for a long time, long 
before any one had even the slightest idea of what a biological 
laboratory was, and further that such laboratories have existed for 
about twenty years, we might really expect that, under the much 
better conditions for the study of the fresh-water organisms, knowledge 
of their biology might have been more advanced in these last twenty 
years. This, however, is by no means the case. The laboratories have . 
