HATCHING-HOUSES AND APPARATUS. 57 



somewhat peculiar. The old plan was to fasten 

 them on with small tacks, but as the flannel 

 rapidly rotted, it was a work of some time and 

 labor to renew them. Our present plan is, to 

 make two frames, fitting one within the other ; be- 

 tween these the filters are fastened, in the manner 

 of a drum head. They can readily be removed 

 and washed, or, if necessary, replaced. 



No whitewash should be used in 01 on the build- 

 ing ; a small fragment falling into the nursery 

 trough might cause the death of thousands of 

 young trout. Lime, in any form, seems to be 

 peculiarly fatal to them, and must be avoided ; 

 and no paint of any description should be placed 

 on any wood work on which young fishes are to 

 be kept. 



3* 



