150 THE TROUT 



eggs and also to the newly hatched fish. A dim light 

 suits them best. The interior of the hatching-house 

 should therefore in the daytime be shrouded in twilight. 

 But you cannot work in the dark ; light therefore 

 should be admitted as and when you require it through 

 windows or skylights screened by movable blinds. 

 These blinds should be kept closely drawn, especially 

 on the south side, at all times except when you are 

 actually at work. 



The exclusion of the sun's rays helps to keep the 

 temperature even, and to prevent the growth of a 

 fungus which strong light has a tendency to foster. 

 But there are worse enemies than the sun's rays to be 

 shut out. Rats, mice, weasels, birds, &c., prowl and 

 hover around bent on plunder ; therefore have a well- 

 fitting door, and let this door be provided with lock 

 and key, and on no account allow visitors to enter 

 unattended. Smoking in your hatchery should be 

 1 strictly prohibited.' 



To secure the necessary fall the house should be so 

 arranged or situated that the water may enter the 

 room several feet above the floor. For this purpose 

 the soil can, if necessary, be excavated, and the floor 

 sunk to the required level ; or the building can 

 be erected on lower ground. This will enable the 

 hatching-boxes to be raised to such a height as to be 



