472 Transactions.—Miscellaneous. 
unless it has plenty to eat. But my difficulty is, within reasonable bounds, 
in such a paper as this, to do justice to what I have sketched out in my pre- 
ceding remarks. And not only so, but without a knowledge of what I have 
yet to say, and which overlaps in many ways the former, these former 
statements themselves would be practically unintelligible. I may, however, 
here describe as shortly as possible these relationships between inert matter 
and trout life, and leave further and fuller details to what has to follow 
when they become necessary in dealing with the growth and habits of our 
trout. 
The geological formation of a river’s water-shed, then, is the basis or 
origin of nearly all loose rocks, stones, gravel, sand, clay, and loam, which 
form the banks or bed of that river. According to the nature of the soil in 
the vicinity of a river, so is its fertility or otherwise—altitude, climate, and 
exposure being also factors. The fertility determines the abundance of 
vegetation, on the land and in the water, and that the supply of insect life, 
of molluses, crustaceans, etc., all the staple food of our trout. 
Again, the meteorological influences at work are by no means con- 
temptible. Heavy floods in the spring or winter before the ova begin to 
hatch out are believed to tear up and wash away the spawning beds or 
‘‘redds.” Lowness of rivers, with frost, after spawning, is also fatal to 
ova, but that is not likely to affect many of our waters. Floods, however, 
must also wash away and kill the eggs or larve of aquatic insects, as well 
as of the Ephemera and Diptera (the flies of our summers), so injuring the 
food supply of the future. On the other hand, droughts during summer in 
very warm weather, result in the growth of low organisms, Fungi, and Alge, 
especially, but not necessarily, where there is bed-rock. Anglers know too 
well here the ugly green weed they name “ blanket weed,” which entangles 
their lines at every cast; and although it may contribute to the production 
of minute species of fish food, it must sicken and cannot improve the health 
of our trout. Wind, too, by its agitation of long deep pools, causes a mud- 
diness of water, and drives all surface food to leeward, killing it at the same 
time. Certain winds on some waters have a marked effect in contributing 
to the feeding or the prevention of feeding in trout. 
In like manner much might be written on the consequences of changes 
in atmospheric pressure, which there is reason for thinking have a good 
deal to do with the times when trouts are on the move. So, also, as to the 
essential health-preserving qualities of water which contains plenty of air in 
solution, and of common salt. But I must now proceed from these con- 
siderations, to gather together and lay before you the actual position of 
the trout experiment in our waters at the present time under these 
conditions. 
