14 DOMESTICATED TROUT. 



much to do with the degree of temperature at which 

 trout will live. For instance, when water does not pos- 

 sess much vigor, is deficient in quantity, and sluggish, 

 it will not support trout life in so high a temperature as 

 when it is vigorous, plentiful, and rapid. I think it is 

 safe to say that sluggish flat water at 70 is dangerous, 

 if not fatal, to trout ; while they will live in vigorous 

 rapid water which occasionally runs to 8o°. I have 

 found 85° to be fatal to them in all kinds of water. 



4. Be sure that the water you select is intrinsically 

 favorable to trout. Be very careful about using any 

 brook or spring which can possibly receive the dis- 

 charge of a tannery or mill, or drainage discharging 

 any poisonous substance. The presence of some lime 

 in the water naturally is not necessarily an objection ; 

 for trout do live in limestone regions, and in water 

 having some lime in it. So of iron ; but too much of 

 either in the water will kill them. The best test of 

 this point that you can possibly get is that the 

 stream is a natural trout brook. On the other hand, if 

 it is not a natural trout brook, or has not been one, be 

 very shy of it ; there is some good cause why trout 

 do not inhabit it, and the cause is probably to be 

 found in the unsuitableness of the water. 



It is no objection to a stream where trout are raised 

 that it is occasionally turbid, or even muddy. Such 



plication, nor can I find a better word to give my meaning. In 

 drinking water, we distinguish between that which is flat and 

 that which is sparkling. What we call sparkling water, when 

 we drink it, I mean by vigorous water in a trout brook. There 

 are very great differences in this respect, as all are aware. 



