[3] FOOD AND SPAWNING OF CARP. 1145 



period of twenty-four hours— the normal .spawning time of the carp- 

 effect the impregnation of from 600,000 to 700,000 grains of roe, which 

 are to be ejected within that same period of time. If Mr. Dubisch is 

 correct, the fish would be much less dependent on the temperature of the 

 water than they really are. So far, therefore, I share the general opin- 

 ion that the grains of roe are impregnated outside of the female fish. 

 The denser the mass of spermatozoa in the water the larger will be the 

 number of eggs which are impregnated, and having immediately be- 

 come sticky, adhere to blades of grass, &c., and the less will be the 

 number of eggs which fall to the bottom without being impregnated. 

 The very circumstance that there are unimpregnated eggs seems to in- 

 dicate the probability that the view generally entertained is correct. 



It would be possible to get at the truth if a female fish engaged in 

 spawning could immediately be examined microscopically. Professor 

 Benecke, who has already put all fish-culturists under many obliga- 

 tions, would again earn our deepest gratitude by solving this exceed- 

 ingly interesting problem. He has already proved the important fact 

 that the spermatozoa of fish do not confine themselves to entering the 

 ovary through the micropyle, but that they (at least in the case of the 

 sticklebacks and probably also in the case of other fish) pierce the sides 

 of the ovary in different places and thus effect impregnation. This pe- 

 culiarity explains the fact that it is easier to produce bastards of fish 

 than of higher animals, where, according to Professor Eueff, the sperm- 

 atozoa strictly confine themselves to the micropyle, and here need a 

 corresponding size and shape. 



I consider it utterly impossible that carp can spawn thoroughly twice 

 a year. The production of from 600,000 to 700,000 grains of roe in one 

 year is such an enormous undertaking for a carp that more can hardly 

 be expected. An exceptionally fine female carp, which, after it had 

 already spawned in Kaniow, spawned in my pond for three years in 

 succession, and which annually produced about 60,000 young carp, 

 finally showed withered fins, an indication that this exorbitant produc- 

 tion had been too much for her. 



Wherever fish have been observed to spawn late in the season, they 

 have been prevented from spawning in spring either by some slight 

 bodily injury or by being still too young, or by having been placed pre- 

 viously in too cold water, where spawning, of course, could not take 

 place until these evils had been remedied and all the necessary condi- 

 tions had been supplied. As in analogy with other animals we must 

 presume that both father and mother transmit some of their charac- 

 teristics to their offspring, it will be necessary with peculiarly fine 

 breeds to put only one male and one female together for the purpose of 

 spawning. Wherever the main object is to produce a large number of 

 fish it is customary, and entirely to the purpose, to put two or three 

 milters to one spawner. There i's considerable difference of opinion as 

 to the proper proportion between the number of spawners and milters. 



