FISH CULTURE. 925 



any other. The flannel should be tacked on frames running in grooves set at an angle of 

 forty-five degrees, (the top down stream,) so as to expose as much surface as possible to the 

 water. If the hatching house is small, the filter may be placed outside, but is better under 

 cover. If the spring is well protected the screens will not need cleaning very frequently. 

 They should be cleaned as soon as they look dirty, however often that may be, and can be 

 cleaned best by being taken out and washed with a soft brush. 



A filter can be made with sponges placed in a box with the water introduced at the top and 

 brought out at the bottom, provided there is fall enough. The box should be about thirty 

 inches long and twelve wide, and a board perforated with holes should be placed below the 

 sponges, and leaving a space between them and the outlet pipe. This will answer on a 

 moderate scale where only a small amount of water is used, and only a few hundred thousand 

 fish hatched, and the sponges will remain clean for months. There should be an overflow 

 pipe from the top to make sure that there is a sufficient supply of water and to carry off the 

 surplus. 



Sediment falling on the egg keeps the water off and destroys its life as effectually as being 

 buried in the ground would destroy a man s life. If sediment falls upon the eggs it may be 

 removed by gently agitating the eggs with a feather, or better still, by creating a current in 

 the water with a feather, which current the eggs will follow, and as they roll over, the sedi 

 ment will drop off. But the trout breeder has no business to be troubled in this way. If his 

 apparatus is rightly constructed, and his filter properly attended to, there will not be sedi 

 ment enough in the troughs to hurt the eggs, from the time they are put in until the fish are 

 hatched out. The pipe which is let into the spring should have wire netting around it where 

 the water comes in, to keep out impurities. This netting should be spread out so as to give a 

 greater surface than the mouth of the pipe. If the netting covers only the mouth of the pipe, 

 every speck of dirt which lodges on the netting diminishes by so much the supply of water; 

 but if the surface of the netting is increased, much of it may be stopped up without lessening 

 the supply of water. The best way is to make a box, say one foot square for each inch of 

 diameter of the pipe, and run the pipe through a hole in the middle of the board, fitting it 

 well; then fit a screen of netting on the front side in grooves so that it can be taken out and 

 cleaned. This should be looked after occasionally, but if the spring is closely walled up, and 

 the netting placed beneath the surface of the water, it will not probably need cleaning through 

 the season. 



Gravel for Troughs. The gravel for the troughs should be quite fine about the size 

 of peas. It is better to use wire screens, as will be explained hereafter, but where only a few 

 eggs are to be hatched and it is important to avoid expensive preparations, gravel will answer. 

 It was formerly used altogether, but is now almost wholly discarded. It is better to have it of 

 a uniform size. Any kind of gravel is good which is free from iron rust, as that kills the 

 fish. If the gravel is of some dark tint, the dead eggs, which turn milk white, will show very 

 plainly upon it, and may easily be picked out. The gravel should be well washed before use,. 

 and we would even recommend boiling it, to destroy any eggs of insects which may be 

 adhering to it. After the nests are prepared the gravel may be put in, one and one half inches 

 deep, which will bring it within one-half inch of the top of the cross-piece. 



Implements. The implements of the fish-culturist are few and simple. A few feathers 

 may be kept on hand to use in spreading the eggs when placing them in the troughs, in col 

 lecting them for packing, and moving them in the search after dead eggs. Several plans are in 

 use for removing dead eggs from the trough. Some use a siphon to draw them up ; others 

 bend wire into the shape of a small spoon, or bend an eye upon the wire just large enough to 

 hold the egg. We recommend the use of nippers. These may be made of wire or some 

 elastic wood like red cedar, bent or cut into the shape of the letter U, elongated to about six 

 inches, and with loops of wire at the ends about the eighth of an inch wide. These will hold 

 the egg without trouble. A small homoeopathic phial is used to examine the eggs. The 

 manner of its use is to fill it with water, put in the egg to be examined, cork it, hold it up 

 before the window in a horizontal position, and with your microscope look up through the side 

 of _ the phial. This brings the egg which lies at the bottom of the glass within the focus of the 

 microscope, and the water does not distort its shape. This seems to be a very simple thing, 

 and hardly worth telling, but of the hundreds who have tried to examine eggs in our hatching 

 house, not a half dozen got it right until told how to do it. The microscope need not be very 

 strong ; one magnifying eight or ten diameters is amply sufficient. A small net will be of 

 use in removing the young fish and any refuse in the water from the troughs ; it should be 

 about six inches in diameter, in the shape of the letter D, with the handle on the middle of the 



