VIU .PEEFACE. 



science, but how many valuable secrets remain 

 to be explored I , 



The mere artificial hatching of fish is by no 

 means a difficult operation if a plentiful supply 

 of clear and cool water can be obtained. But 

 the points chiefly to be considered are, how are 

 fish to be fed and fattened when they are hatched ; 

 what suits them, and what does not ? There is 

 no difficulty in producing any number of fish^ 

 but the rearing them until fit for food is another 

 matter. We often hear of the fish in certain 

 waters dying off without being able to discover 

 the cause. Some weed, or insect, or other 

 matter which is very prejudicial to fish, may 

 have become mixed with the water j and we 

 Ought to be able to detect the cause at once, 

 and with certainty. We ought to know how 

 such things are to be prevented, and what the 

 diseases of fish spring from. But we do not. 



The agriculturist knows to a head or two 

 what amount of stock his farm will carry. He 

 knows what kinds of roots are best suitedj 

 not only for stock to feed on, but for his 

 various fields to grow. The cold land suits 



