OF CERTAIN KINDS OF FISH. 19 



spermatic fluid from the male being received into 

 the vessel containing the water and eggs, the eggs 

 should then be stirred about very freely in the 

 water, and suffered to remain ten or fifteen minutes, 

 when the water should again be changed, and after 

 a short time this change should again be repeated. 

 It is thought by some persons, that the eggs should 

 be stirred or rinsed, and the water changed before 

 the spermatic fluid is added. The precaution, I 

 think is a good one, as it serves to remove any 

 mucus, with which the eggs are more or less, 

 covered, and which to some extent may prevent a 

 perfect contact of the sperm with them. 



A very small portion of the spermatic fluid is 

 sufficient to impregnate the eggs of one female; in 

 fact, the sperm of one male is sufficient to impreg- 

 nate the eggs of half a dozen females. 



I have recently read an extract from a foreign 

 journal, which stated that Dr. Robertson, of Dun- 

 keld, (Scotland, I suppose,) denies that the eggs 

 are impregnated after they are extruded from the 

 female, but contends that they are impregnated 

 previous to their development within the body of 

 the fish. If actual observation or experiment con- 

 firms this statement, there will be no necessity of 

 obtaining the sperm or milt of the male fish, 

 which at present is considered indispensable. I 

 cannot give my assent to this statement, for the 



