fish was becoming sensibly diminished and must 

 before long altogether fail, that attention in Michi- 

 gan began to be called specially to the subject of 

 fish culture. 



As in other departments of labor, particularly in 

 those engagements which involve considerations 

 relating to the natural order of things, the success- 

 ful prosecution of pisciculture requires a careful in- 

 duction of conditioning principles together with 

 much experience in the application ol those princi- 

 ples to different cases, both under the same and also 

 under diverse circumstances. We can become 

 acquainted with the principles underlying successful 

 pisciculture only by observing the conditions and 

 circumstances attending the inception and develop- 

 ment offish in their native haunts. 



Much wasteful expense and discouraging failures 

 have resulted from disregard of this simple and 

 obvious fact. Nature is the only proper teacher of 

 her own laws, and true methods can be learned in 

 no other school of art than that in which she presides. 

 As the farmer needs to know the nature of the soil 

 on which a given plant spontaneously grows, the 

 circumstances of climate, season, etc., under which it 

 naturally develops ; the nature, habits, etc., of the 

 plant itself, so the pisciculturist must understand the 

 peculiarities of the water which a given kind of fish 

 naturally inhabits ; whether it is salt or fresh, pond or 

 spring, lake or brook, etc., must know the time of 

 year, temperature of water, etc., in which the parent 



