100 FISH CULTURE. 



taken. Here sport with the fly is generally good, 

 because the lake is shallow and clear, and the fish 

 see the fly well. In other lakes, again, where these 

 species of weeds, which form the harbour and sub- 

 sistence of these insects, are wanting, it will usually 

 be found that the trout are small, or, if large, ill-fed 

 and meagre. I know also a small lake in Wales, 

 where the fish never take a fly until after dark, when 

 fish from 2 to 31bs. weight fan unusual size for Wales) 

 may be taken. This lake abounds in leeches, and 

 the trout are very fine in it. A quarter of a mile off 

 is a similar lake, in which trout do not thrive at all, 

 and, indeed, are seldom found ; while about a mile 

 from it are one or two small lakes, in which the trout 

 do not average three ounces. And yet the character 

 of the lakes, and the soil in and about all of them, 

 are apparently precisely similar. 



It cannot be doubted that the condition and size of 

 trout, as well as other fish, depends almost wholly 

 upon the supply of food, and I think I have shown 

 that the particular kinds of food are also a great 

 desideratum. Now, it being known that particular 

 kinds of weed are favourable to the production of 

 these certain species of insects, what can be easier 

 when the soil is favourable to such a measure than 

 to transplant a sufficient quantity of these weeds, and 



