[11] ARTIFICIAL FEEDING OF CARP. 1019 



all cases where artificially introduced food forms the exclusive food of 

 the carp. 



This is the case, for exarni)le, where feeding is intended to aid in stock- 

 ing a pond with more fish than its natural conditions of food will allow, 

 if a certain weight of carp is to be obtained. In this case, the food to 

 be introduced would, so to speak, be the only food for the fish above the 

 number naturally belonging to that pond. The case would be similar 

 wherever fish are to be kept in a walled basin. 



The more nitrogen the food contains, all tlie more profitable will the 

 feeding be, for if more hydrates of carbon are fed to the fish than the 

 l)roper proportion of the nutritive substances demands, these and the 

 money spent for them is wasted, as they either pass from the body with- 

 out being of any special use, or are used in the vital process without 

 creating any flesh. 



Wherever artificial feeding is merely to increase the productiveness 

 of a pond, one may more or less, or even entirely, abandon the idea of 

 mixing food for the ])urpose of widening the standard proportion of the 

 nutritive substances (*. c, of adding, in food not containing much hydro- 

 gen, the necessary hydrates of carbon to the food containing much al- 

 bumen), as in nearly all organic matter the quantity of hydrates of car- 

 bon far exceeds that of the i)roteine, so that the fish can easily satisfy 

 their demand for such hydrates of carbon from tlie natural resources of 

 the pond. 



The mixing of food, however, will be necessary, if it is not to be im- 

 mediately eateu by the fish, in order to put the food in suitable shape, 

 so as to prevent its losing its strength by being soaked in the water. 

 Such preparation will also be necessary when it is to be kept for any 

 length of time. For the sole purpose of meeting the last-mentioned 

 object, it will suffice to mix the food with clayey or loamy soil. Thus, 

 e. g., by mixing a suitable quantity of water with meat-flour and some 

 soil, an evenly mixed tough paste is produced, which is shaped into 

 balls of the size of a pea or a filbert, or into small cubes, which are 

 dried in the air. Food thus prepared only soaks very gradually in 

 water, and takes a long time to dissolve entirely; which, however, haj)- 

 pens but rarely, as the fish will devour it as soon as it has become some- 

 what soft. 



It is not advisable to form this and other mixed food into thin cakes, 

 similar to the Jewish Easter bread, which are broken and thrown into 

 the water, as they will sink to the bottom, where it is difficult for the 

 fish (o get at them, and, sinking deeper into the mud, are finally lost. 

 This is my own observation. For young fry, meat-flour, malt, bran, &c., 

 may be scattered on the grassy banks of the ponds. 



In designating those articles of food which contain the largest quan- 

 tity of nitrogen, as the most profitable, I take it for granted that a per- 

 son is exclusively limited to the buying of food. Wherever this is not 

 the case, where other agricultural industries are carried on in conuec- 



