On Stocking. 27 



linings of any sort, but the general public still delight in 

 providing all sorts of death-traps, under the name of shelters. 



( After the fry have herded together for a few weeks, more 

 or less, according to the temperature of the water, they are 

 seized with a roaming and inquisitive spirit. At this stage 

 the use of flannel in fixing the safety-screen becomes 

 apparent. But it must be new flannel ; old sodden stuff is 

 certainly water-tight, but still the fry manage to burrow be- 

 neath it, and, although they cannot pass through, manage to 

 suffocate themselves in considerable numbers. New flannel 

 is seldom water-tight, but this is of no consequence. Whether 

 the fine hairs annoy them, or whether inherited instinct 

 teaches them to dislike the manufactured product of the 

 animal whose periodic washings have so frequently nauseated 

 their ancestors, I know not ; but it is nevertheless a fact that 

 the alevins will test every joint in the box, but leave the 

 flannel-protected joints of the safety-screen alone. 



' The only attention newly hatched alevins require is as to 

 the strength of the current passing through the safety-screen. 

 If the water is kept shallow, and the current equivalent to two 

 gallons per minute through the ordinary Howietoun hatching- 

 box, there is some danger, during the first few hours of the 

 hatch, of so many of the holes of the perforated zinc of the 

 safety-screen becoming clogged with cast-off shells as to make 

 the current sufficiently strong through the remainder to catch 

 and hold any unfortunate alevin passing. It is not safe to 

 heighten the water in the hatching-box by placing flannel on 

 the outlet screen before nine-tenths of the eggs are hatched, 

 or the decreased current will cause partial suffocation of the 

 embryos. And even when one-tenth of the eggs are left, 

 they should be well separated with a feather before the water 

 is deepened. If alevins get against the safety-screen, the 

 pressure of the water gradually forces the yolk-sac, which is 

 very elastic, through one of the perforations of the zinc. If 

 No. 9 size is used, little harm accrues, as a strong alevin, so 

 soon as he feels the process commence, can free himself by 

 his struggles ; and he takes care in future to avoid the screen- 



