THE NURSERY. 87 



It is necessary to have even the opening where the 

 water falls in protected by a wire screen. 



One autumn I lost several hundreds of fine trout, 

 three inches long, by something, I never knew what, 

 entering the boxes where the water came in. 



The cover can be made of wooden slats, if preferred ; 

 but they should be very close, for snakes, which are 

 very destructive to young fish when confined, will ven- 

 ture through holes which are big enough to admit 

 their bodies. 



8. Perfectly tight joints. Only a person who has 

 had many years' experience in raising young fish 

 knows the whole significance of this precaution. The 

 knack which young trout have of going through very 

 small crevices is almost incredible. I once made a 

 solid bank of fine hatching gravel a foot long, to hold 

 some young fry. In a week three hundred had found 

 their way through it. I venture to say that there is 

 not a trout breeder who reads this page, who has not 

 lost more or less young fry, through some unnoticed 

 crevice in their place of confinement. 



It seems as if they had the gift of flattening them- 

 selves almost indefinitely. At all events, they will 

 squeeze through a wonderfully small crevice, so that 

 the only safe way is to examine the box or trough 

 thoroughly and make every joint perfectly tight. If 

 this cannot be done effectually with hammer and nails, 

 the places should be calked with flannel, or something 

 similar. The outlet screen should be as fine as eigh- 

 teen threads to the inch. With anything larger than 

 that, the fry will get their bodies through, and hang 

 themselves by the neck. 



