[3] ARTIFICIAL FEEDING OF CARP. 1011 



of these two uaturalists has no bearing on the question before us, and 

 we will, therefore, leave it undecided which of the two is correct. 



Comi^ared with hind animals, tish can, therefore, in an equal quantity 

 of food, obtain more albuminous matter than the former, and thereby 

 also attain to a larger growth, as, up to a certain limit, the formation 

 of flesh and fat in the animal body increases with the increased quan- 

 tity of albuminous matter contained in food. 



If we further compare the proportion of the various nutritive sub- 

 stances contained in the natural food of the carp with that found by 

 us as the standard of food, this standard will be found to be correct, 

 even when viewed from this standpoint. 



The natural food of carp consists of worms, maggots, larvte, snails 

 beetles, and other insects. Of these only the beetle and a number of 

 other insects have been examined as to the quantity of nutritive mat- 

 ter contained in them, and they have been found to contain on an av- 

 erage 95 per cent, of nitrogenous matter, which would correspond to a 

 nutritive proportion of 1 : 0.05. This proportion in cockchafers is given 

 by Professor Wolff as 1 : 0.6. 



As regards the worms, snails, t&c, we possess no data, at least none 

 have come to my knowledge. The effect of these animals when used 

 as food for fish, however, shows that they must contain a considerable 

 qnantity of nitrogen. Thus the " Deutsche Fischerei-Zeitung,^^ 1880, p. 25, 

 maintains that by feeding trout on worms their weight can be increased 

 in one year from three-fourths of a ponnd to 2i pounds. Although this 

 may be somewhat doubtful it nevertheless shows that the quantity of 

 nitrogen contained in worms is very similar to that contained in beetles 

 and other insects. 



As regards feeding fish on snails. Dr. Molin says, in his Rationellen 

 Zucht der /Silsicasserjische^ p. 13, that Commander Desme had a pond 

 containing 150 hectoliters of water on his farm at Puygirard, in which 

 he fed young salmon and trout on pounded snails, by which method of 

 feeding he increased their weight on an average by 1 pound per tish. 

 It may, therefore, be safely assumed that the quantity of nitrogen in 

 snails is not materially less than that in worms. 



As carp take the above-mentioned articles of food mixed, and as some 

 of them consist exclusively of nitrogenous matter, and, as in most of them, 

 the i)roportion of nutritive matter is a very close one, the standard of 

 food laid down by me will also, from this point of view, have to be 

 acknowledged to approach very closely to the natural food of the carp. 



I have started my theory from the fact, which I know from actual ex- 

 perience, that the food of the carp is principally animal and not vege- 

 table matter, and I find that in tliis I agree with most of the practical 

 pisciculturists; but I differ from the views of Professor Nawratil 

 {Oesterreichisch-Ungarische Fischerei-Zeitung, 1880, No. 35)* when he as- 



* The Fiticherei-Zeitung, formerly published in Vienna, is now discontinued, and not 

 to be confounded with the first Oeslerreiclmck- Ungarische Fincherei-Zeitung. 



