1124 EEPOEt OF COMMISSIONER OF FISH AND FISHERIES. [24] 



uralists have not yet deigned to make such exceedingly simple experi- 

 ments which are of the greatest importance to them. Nothing is needed 

 for such experiments but a number of ponds of the same character, 

 whose size is known. These ponds should be stocked with the same 

 carefully ascertained weight of carp of equal size per are; in one. of 

 these ponds no food should be given to the carp, and in the other ponds 

 different articles of artificial food, whose price is well known, should be 

 fed to the fish, in even quantities 5 and during the autumn fisheries the 

 increase of weight per are should be calculated for every pond. 



For the time being we do not feel justified in recommending any par- 

 ticular food, and can only mention the kinds most commonly in use ; 

 and any one may from this list select those which he can obtain cheap- 

 est. The food is thrown into the water near the edges of the pond either 

 by itself or kneaded together with clay, and it will soon be seen whether 

 the fish take to a food or not. This is of special importance in ponds 

 through which flows no river or brook, as food which is not consumed 

 by the fish would decay in them and pollute the water. Some people 

 recommend the dung of cattle, sheep, and hogs, also fine flour, bran, 

 husks, maltsprouts, boiled lentils, beans, lupines, peas, potatoes, tur- 

 nips, the solid refuse from distilleries, the remnants of beets from sugar- 

 refineries, the refuse from dairies, boiled blood, &c. It may be well to 

 mix a number of these articles and knead them with clay. In some 

 places some of the articles of food mentioned above, mixed with clay, 

 are made into flat loaves, which are dried either in an oven or in the 

 sun, and can then be kept for a long time. Occasionally snails, cock- 

 chafers, and worms — wherever they can easily be obtained in large quan- 

 tities — may be mixed with this food. It is not advisable to throw into 

 the ponds the flesh of worthless animals ; it is especially to be avoided 

 to have entire dogs, sheep, or quarters of beef or horses thrown into the 

 pond, as is done in some places, because the water easily becomes pol- 

 luted thereby, ^nd because the fish cannot bite ofl; pieces. They can 

 only eat such articles of f»od as they can take into their mouths and 

 devour at once. They always like meat chopped fine, especially if it is 

 mixed with flour. 



Eecently various articles of food mixed on scientific principles have 

 been recommended, and it is very desirable that they should be sub- 

 jected to a systematic examination; wherever a systematic method of 

 feeding will quickly, and without any great outlay, increase the yield 

 of ponds, it is of course to be recommended. 



9. The relative size of the ponds. 



As in agriculture, so in pond-culture, a rational use of a given area 

 only becomes possible, if based on a proper system. It is of special 

 importance to maintain the proper proportion in the relative size of the 

 spawning-ponds, the raising-ponds, and the ponds for older fish. If 



