126 FISH CULTUEE. 



the introduction of the anacJiaris alsinastnmi, and its 

 attendant insects, would have a very favourahle effect 

 on the size and flavour of the trout found in such 

 places. It would in time hecome a very interesting 

 and valuable fact, to hear that Mr. So-and-so had 

 brought home a new water-weed, favourable to the 

 production of certain water insects, from Lake Ifyanza 

 or elsewhere. There must also be a vast number of 

 water insects, which would prove valuable to our 

 fisheries if introduced, provided we knew all about 

 them. There are hundreds — nay, thousands — of lakes 

 in Ireland and Scotland that are now worthless, pro- 

 ducing nothing but wretched little starved trout of 

 ten to the pound, which might more or less be con- 

 verted by these means into valuable properties. 



I think I have said enough to show that there is 

 here a very wide field for discovery. Here is, as I have 

 said, a new world — a new science to be learnt. The 

 modem taste for aquariums and vivariums has given 

 us some small insight into how to cultivate those 

 plants which we already possess, but we do not 

 study even these to discover the natural duties and 

 uses for which Providence designed them. "We do 

 not in a like manner work out the properties of the 

 insects that inhabit them ; and what could be more 

 easy, or would be more interesting, to the entomo-i 



