598 CONFERENCE OF DELEGATES 
for some years, samples have periodically been taken at various points in 
the stream. The effects of sewage, gas-works effluents, and other sources 
of contamination were apparent, and having obtained sufficient scientific 
evidence to show that these sources of pollution had a detrimental effect 
upon the health of the river fauna, and were therefore likely to be detrimental 
to the health of human beings, interviews were arranged with the various 
parties concerned. 
The nature of the filthy and evil-smelling slime which stifled the vegetation 
and made animal life impossible in the vicinity of sewage outfalls, told an 
obvious story. As a result, improvements have been made in the method 
of treating the sewage, and in preventing poisonous gas liquor from finding 
its way into the river, all of which is to the good. 
The reports of the various observers of the macroscopic and microscopic 
fauna and flora, as well as the marvellous series of observations on the 
chemical and other properties of the water carried out month by month by 
Mr. N. C. Akers, have indicated certain directions in which experiments 
might definitely be made to ascertain the effect of the polluted water upon 
the fish in different parts of the river. For this purpose, with the aid of the 
Yorkshire Fishery Board and the local angling societies, large numbers of 
different species of fish were secured, and placed in specially designed cages 
at selected points of the river, and periodically examined. So far, however, 
the experiments have been largely of negative value, though we have been 
able to ascertain what to avoid in dealing with captive fish. 
In the first place, most freshwater fish suffer by being handled, and still 
more during transport—so much so that the damaged scales, etc., readily lend 
themselves to the growth of a fungus which quickly causes a large mortality. 
Similarly, if the cages, though kept under water and with facilities for 
the fresh water to pass through, are too small, or unsuitable in their con- 
struction, and the fish damage themselves and thus soon die. Further, also, 
marking the fish in different ways before allowing them their freedom in 
the stream has given negative results, as none of the hundreds of marked 
fish has been recovered. At the present time trout, and ‘ goldfish "—which 
seem to be immune from many of the troubles referred to—are being subject 
to experiment. In any case the work has proved to be exceedingly interesting 
from a scientific point of view, and before our labours are completed we hope 
that results of a practical nature will accrue. 
At the same time, however, as years go on, increasing population on the 
banks of the river and on its tributary streams, together with the necessity 
for disposing of the waste liquors from the factories which increase in size 
and numbers, all militate against a return to the ‘ good old times.’ But 
the Ministry of Agriculture and Fisheries considers that the work done in 
East Yorkshire by amateur zoologists, botanists, chemists, and others might 
easily be undertaken in other areas ; and the object of these notes is to suggest 
to the delegates that they consider whether they can help; and I am assured 
that the Ministry will give every facility and place its accumulated records 
at the disposal of any society inclined to take up this fascinating work. 
As one who has missed but very few of the scores of meetings which have 
been held dealing with nearly all aspects of the question, I can assure you 
that the investigations are full of interest. 
There are other aspects of the matter which I have not dealt with, but which 
are bound to arise, namely, the legal questions, which are keenly watched 
and contested by the legal representatives of the different parties. ‘These 
difficulties and the wonderful arguments which have been brought forward 
are, I fear, beyond me; though they have been quite entertaining! This 
particular subject was dealt with by Mr. H. F. Atter in Section G yesterday. 
