122 SEASON 1874-75. 



Simplicity for working is the next thing to be considered. 

 There must be no crevices for dirt to lodge, or young fry to 

 suffocate under ; there must be no part of the box out of sight ; 

 the whole bottom, when there are fry, and every egg, when there 

 are ova in the box, must be capable of being searched at a 

 glance. 



The sides of the box above the ova should allow the removal 

 of dead ova with ease, as, if the sides are too deep, the attendant 

 will disturb other eggs, which, especially for the first month or so, 

 is highly undesirable ; if the sides are not high enough when the 

 water is heightened for the fry, they can and will jump out. 



The ends of the hatching-boxes should be made to catch all 

 the water from the overflow without projecting unnecessarily into 

 the hatching-house. All the fittings for the grilles should be 

 removeable, and taken out with the grilles ; this leaves the bottom 

 of the box clear for the fry. In the first boxes at Middlethird I 

 left the ledge which supports the grilles solid on the side. This 

 entailed too much labour, and wasted too much wood ; but I 

 mention it to show how the Howietoun hatching-boxes have 

 originated. 



Protection from injury is now an easy matter, but at that time 

 I did not know what to protect against. The first danger that 

 showed itself was mice. These little rodents have a partiality for 

 trout eggs, and made a great mess in the boxes at the beginning. 

 But they left foot-marks one wet morning on the edge of the 

 hatching-box, and the murder in my eyes it was nothing less 

 was out. A trap supplied at once the punishment and the 

 evidence of crime. Lids were made and fitted, and the eggs were 

 safe. Light is a danger against which ova require protection. I 

 do not know the reason as yet, but I have compared many millions 

 of trout eggs, some hatched in total darkness, some in a dim light, 

 and some in ordinary daylight ; but the sun has always been 

 excluded. The principal effect of light is premature hatching. 

 Small eyes in the embryo are much more frequent where the eggs 

 have been exposed to light, and if these small eyes are frequent 

 in any box, the best thing to do is to throw them away ; they are 



