570 REPORT OP COMMISSIONER OF FISH AND FISHERIES. [104] 



kept moist, so tightly that they cannot stir, and if fed on the food 

 described above they will grow fat ia a very short time and acquire a 

 most delicious flavor. Another means of fattening fish is to castrate 

 them. This operation was first tried in England, not only on carp, but 

 also on pike and other fish. It seems, however, that the great ex- 

 pectations entertained in regard to this method were not realized."* 



Unfortunately, the above data do not contain the slightest hints as 

 to the quantity of food, and also leave ns entirely in the dark as to the 

 results (in figures). They are, nevertheless, exceedingly valuable for 

 making experiments, and because they show what articles of food were 

 used successfully by former pond cultivators. In all probability it would 

 pay even in our days to employ such food. We also learn that the food 

 consisted principally of those products of the vegetable kingdom which 

 contain a great deal of albumen. Tlie articles of food described above 

 were generally employed i4i small recei)tacles such as fish tanks, and the 

 only one among the older authors on the subject who states that they 

 may with as much advantage be employed in ponds is Jokisch. It may 

 be presumed, however, that the articles of food mentioned by the other 

 writers may be used in ponds as well as in tanks. We will cite tlie 

 following interesting example, Avhich shows liow ])rofitable tlic artificial 

 feeding of carp maybe. The papers contained an account of a (Icrman 

 by the name of Poppe, residing in California, who imported carj) from 

 Germany and placed them in a pond containing warm springs. The 

 carp were ied on blood, thick milk, refuse from slaughter-houses, i!s:c., 

 and grew marvelously. When placed in the pond they measured 15 

 centimeters in length; after nine months they commence<l to sj)awn, 

 and after twelve months they measured 50 centimeters in length and 

 weighed from 12 to 15 pounds.t Del ins, who gives an account of Mr. 

 Poppe's experiments, says: "These results seem almost incredible, but, 

 by taking into account all the local conditions, we must grant that 

 they are within the reach of possibility. It should be remembered that 

 the water all the year round! had the most favorable temperature of 

 18° R6aumur [72^o F.], and that the development of the fish was not 

 retarded by a single cool day. In one year the original weight of the 

 carp had increased sixty or seventy fold. A young pig at its birth 

 weighs about 6 pounds, and there are instances where the weight of such 

 a pig was in twelve months increased to 400 pounds, which would show 

 about the same ratio of increase as that of the carp referred to above." 

 We regret that we are not informed as to the quantity of food which 

 Mr. Poppe gave to his carp ; but it may be presumed that this develop- 

 ment was reached by employing food which contained a great deal of 

 nitrogen, from which it may be inferred that the carp, in order to grow 



* Tscheincr, p. 191. 

 t Delins, Tcichwirthschaft, p. 28. 



t The growth of tho fish was, thoreforo, not intt^rrnptod durincj winter, ami the 

 twelve mouths are fully eqnal to two years under our couditious. 



