60 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



tlie owners of closed fish-ponds. It is of course impossible to say in 

 advance whether such advantage would be commensurate to the trouble 

 and probable loss of fish by unsuccessful operations. Only the more valu-. 

 able fish, e. g., trout, and perhaps carp, would be fit subjects for such 

 experiments. 



Note. — We have received the following letter on the same subject : 



"Eeferring to the question whether it is possible to castrate fish, in 

 Nos. 52 and 53 of the ' Deutsche Fischerei-Zeitung,' I would observe 

 that the idea is not a recent one. Thus the author of ' Wohlbewahrte 

 Fischgehehnnisse oder deutlicher Unterricht von der grossen N'utzharlieit 

 der Fischerei, wie audi von der FiscJie Natur und Eigenscliaft ; nehst 

 einer Amveisung, ivie sie bequem zufangen, und zu welcher Zeit man solche 

 am Besten halte^ (Well preserved fish-secrets or plain instructions re- 

 garding the great usefulness of fisheries, also regarding the nature and 

 qualitj' of fish ; accomi^anied by hints how to catch fish in the easiest 

 manner, and during what season they can best be kept) ; 2d and im- 

 proved edition, Nuremberg, by George Bauer, 1758, in the chapter 

 entitled ' On the Castrating of Fish ' [von der Verschneidung der Fische), 

 gives the following extract from '■Histoire de VAcademie des Sciences 

 1742, Observations de physique V : ' Mr. Sloane, the former President 

 of the Eoyal Society of London, has written to Mr. Geofiroy, towards 

 the end of December last, that an unknown person had revealed to 

 him the secret how to castrate fish and make them grow fat thereby. 

 This person, who originally was nothing but a net-maker, and had 

 formerly lived 5 or 6 miles from Mr. Sloane's country place, had built 

 up a considerable trade in fish by his skill in managing them. This 

 strange communication excited the curiosity of the naturalist, and 

 the fish merchant-offered to show him the exj)eriment. He took eight 

 bastard carps {Cyprinus carassius), a species of small carp which had 

 recently been brought to England from Hamburg, and placed them 

 into two large vessels filled with water, which was renewed once or 

 twice during the experiment. He began by opening one of these eight 

 carps with a knife, and showing Mr. Sloane the ovarium which opens 

 into that part which is called ' the cloaca.' He thereupon cut open an- 

 other carx), laid bare the ovarium, and closed the wound with a piece of 

 a black hat. The carp which had been cut were jjlaced with the other 

 six, but did not seem able to swim as well as the rest. They were finally 

 all thrown into a small pond iu Mr. Sloane's garden, which is supplied 

 with water from a neighboring river, and v»here, he thinks, they were 

 still living at the time when he wrote to Mr. Geoffroy. Further infor- 

 mation is not given. This man, whose name is Samuel Tull, promised 

 Mr. Sloane, that in spring he would invite him to a dish of cut fish, which 

 were said to excel other fish in flavor as much as a capon a common 

 rooster, and as a cut ox an uncut one. As there is much similarity 

 between land animals and fish, it is probable that castrating has the 



