122 ECONOMIC ZOOLOGY 



be kept cool, which in summer may necessitate the use of ice, and it 

 must be either aerated or frequently changed. It is sometimes possible 

 to keep it sufficiently aerated by dipping it out with a cup and pouring 

 it back from some height. 



In some cases it is desired to ship the eggs to a distant point, where 

 their further development will take place. This is done in various ways. 

 In some instances, light wooden boxes are used and the eggs are packed 

 as follows: a layer of damp material, preferably sphagnum moss, is 

 placed in the bottom; over this a sheet of wet cheese cloth is spread upon 

 which a layer of eggs is laid; over the eggs another sheet of cloth and 

 another layer of damp moss are placed and this is repeated until a 

 dozen or more layers are present, perhaps with a horizontal partition 

 or two of wood to prevent too great pressure on the bottom eggs. This 

 box is now packed in the centre of a larger box with dry moss or other 

 shock-absorbing material and may be sent on a journey of several days' 

 duration. In warm weather various methods are used to keep the eggs 

 cool. 



The above is a brief account of the general methods of fish culture; 

 the method varies with the different species of fish, with the locality, 

 and with other varying conditions. 



There are many farms, remote from the coasts or from large bodies 

 of water, where fresh fish are almost an impossible luxury. In many 

 cases there are, or could be constructed, on these farms, large ponds, 

 often used for the gathering of ice, where fish in sufficient numbers to 

 supply the family could be raised at a nominal cost. If the pond be 

 surrounded by a rank growth of vegetation it will support a considerable 

 number of fish; if the pond be new or have a more artificial environment 

 the fish will probably have to be fed. The kind of fish best suited to 

 the pond will have to be determined by the local conditions. For ex- 

 ample if the water be sluggish carp or cat-fish will have to be raised; 

 if there be a fairly rapid circulation, changing the entire body of water 

 every week, bass or perch may be kept; if the circulation be sufficient 

 to change the water every day or two trout may be raised. The 

 pond may be stocked with a few adults or by planting eggs or fry, 

 which may probably, in most cases, be obtained from the nearest State 

 hatchery or from the U. S. Bureau of Fisheries. Various bulletins 

 upon the subject have been published that give specific directions. 



