[Ill] 



POND CULTURE. 



577 



In 100 poonds of food. 



Per cent, of— 



Water. 



Digestible substances. 



Albumen. 



Hydrates 



of 



carbon. 



Fat. 



Propor- 

 tion of 

 nutiitive 



sub- 

 stances. 

 Nh.=l. 



Grains of wheat 



Grains of oats 



Wliey 



Grains of rye 



Turnips 



Griiins of barley 



Grains of corn (maize) 



Malt, dry 



Potatoes 



Potato fiber, refuse from starch factories 

 E.xcrements of cattle 



14.4 

 14.3 

 92.6 

 14.3 

 91.5 

 14.3 

 14.4 

 7.5 

 70.5 

 8C.0 

 71.0 



11.7 

 9.0 



11.0 

 9.9 

 0.9 

 8.0 

 8.4 

 7.5 

 2.1 

 0.8 

 0.5 



64.3 

 43.3 



5.1 

 65. 4 



6.8 

 59.9 

 60.6 

 67.2 

 21.8 

 13.7 

 12.3 



1.2 

 4.7 

 0.6 

 1.6 

 0.1 

 1.7 

 4.8 

 1.8 

 0.2 

 0.1 

 0.2 



5.8 

 6.1 

 6.6 

 7.0 

 7.6 

 7.9 

 8.6 

 9.4 

 10.6 

 17.4 

 '30.5 



*rrom experiments made on the farm of Mr. J. Schwarz, at Hofgarden, in Sweden, with feeding 

 iiiilch-cows on horse-dunsr, it appears that, as to their nutritive qualities, 300 pounds of hoisc-dnng 

 fire e(]ual to 100 pounds of stiaw. One hundred pounds of straw contain, on an average, the follow- 

 ing' riuantities of digestible nutritive .substances: about 1.5 per cent albumen, 36.9 per cent hydrates 

 of carbon, and 0.5 percent fat, and the average proportion of nutritive substances is 30.5 per cent, 

 therefore the same in 300 pounds of horse-dung, and in 100 pounds of excrements of cattle. (See the 

 agricultural journal Der Landwirth, 1875, No. 71.) 



If the food of the fish is to be thrown into the water, the question will 

 htive to be considered whether in case it has to lie in the water for any 

 length of time it will not lose some of its nutritive qualities. Wherever 

 there is any danger of this it will be necessary either to substitute food 

 Avliich will resist the influence of the water or to envelop the original 

 food in it. Mixing the food with clay will also have a good effect. 

 Cooked food, e. g., the various kinds of grains, i)eas, beans, potatoes, 

 &c., is in that condition less exposed to the influence of the water than 

 when raw. The manner in which pond cultivators in former times pre- 

 pared their food shows that they had the same experience. 



The spoiling of food in the water and the precautionary measnres re- 

 ferred to above may be avoided by giving the food to the fish regularly at 

 stated times and throwing it all into the water at one and the same 

 place not far from the bank, so that one may observe how umch of it is 

 eaten. If the fish have once become accustomed to a regular feeding 

 time and place they will always gather there at that time, and it is said 

 that they will even follow the sound of a bell. It will soon be seen how 

 much or how little of the food is eaten, and tlie quantity of food can be 

 regulated accordingly. It will require a little experimenting to find the 

 right quantity, and all we aim at here is to give a theoretical basis for 

 such experiments. The kind of food, and the proi)ortiou in which differ- 

 ent kinds of food should be mixed, is determined by the proportion of 

 nutrititive substances most favorable for carp, as gis^en above, accord- 

 ing to which concentrated or condensed food is the best, as in other 

 kinds of food there is a waste of hj'drates of carbon. 



The most suitable articles of food, therefore, are blood, horse-flesh, 

 fish guano, curds, meat dried and ground fine, refuse from slaughter- 

 houses, &c. All these, however, require to be mixed with other articles 

 of food containing less nitrogen, so as to restore the proper proportion 

 H. Mis. 68 37 



