1864.] ON PISCICULTURE. 141 



operated upon direct from tlieir breeding-ground, and as short a 

 time as possible before the spawning commences. Where this is 

 impossible, they should be kept in fish-boxes or reservoirs ; care 

 however be taken that they be not kept too long in confinement 

 before being used, as this would have an injurious effect both on 

 the ova and the milt. One male fish is suflScient to fructify 

 the ova of a great many females, and can be used from six to eight 

 days in succession. 



It is not difficult to ascertain when the female \B ready to spawn. 

 Her distended abdomen yields easily to a gentle pressure, and an 

 undulating movement which is perceptible on touching it, shows 

 that the spawn is already disconnected from the ovary. She 

 should then be held by the head in a vertical position, so that the 

 ova will of their own weight fall down towards the vent. When 

 the fish are large, it is best to have three persons to assist. One 

 takes the fish by the head, and the other by the tail, holding it 

 horizontally over a dish, the vent downwards, whilst the third very 

 gently presses along her stomach and sides. When the bottom of 

 the dish has been covered with ova, in layers of two or three deep, 

 the fish can be released into the tub of water from which she was 

 taken. The dish, by the way, must previously have been nearly 

 filled with water. Before operating on the male fish, the water 

 from the fish had better be drained ofi", and fresh poured in. The 

 male fish is then taken and handled in the same way. A small 

 quantity of milt, just sufficient to discolor the water after being 

 gently stirred with the fingers, is sufficient. It is then put back 

 again into the tub, and while the female is agiin being brought 

 out, the contents of the dish are to be emptied into another tub 

 half filled with pure water. When all the roe has been pressed 

 out and fructified as before with the milt, and again emptied into 

 this tub, the water is allowed to run out through a hole pre- 

 viously bored in the side about an inch above the bottom. By 

 the motion of the water running out, all the eggs will be brought 

 into contact with the milt. In about five or ten minutes the ova 

 can then be removed into the hatching-boxes. 



If the eggs are in a fit state, the very smallest pressure is suffi- 

 cient to squeeze them out ; and it has been found that with due 

 care the female suffers no injury from the manipulation, and will 

 be as fruitful the following year as ever. 



The unfruitful eggs, after they have been some time in the 



