474 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



of young fishes, which were dispersed in the Lake of Raexen. If this 

 process had been employed on a large scale in all the lakes of Sweden, 

 there would have resulted, says he, a real blessing for the country. 



The favorable circumstances of the arrangement adopted by Lund 

 enabled hirn to observe some particulars of the development of the 

 embryo. A German naturalist, Bloch,* advanced somewhat farther in this 

 direction by employing a similar means. He took from the Spree some 

 aquatic plants covered with eggs of perch, bream, rotengle, &c., and 

 kept them in a wooden box of fresh water, renewed daily. At the end 

 of a week he obtained many thousands of little fish ; observing, however, 

 that only a small part of the eggs were fecundated, and that those which 

 were so remained transparent and yellow, while those which failed be- 

 came daily more disturbed and opaque. Bloch concluded that l)y 

 transporting spawn upon plants, as he had done, lakes and ponds 

 might be easily and cheaply stocked with fish ; but he made no experi- 

 ment, and, as we see, only imperfectly imitated Lund. 



While the ingenious predecessor of Bloch was seeking the means of 

 increasing the inhabitants of the Swedish lakes, a lieutenant of miltia 

 of Lippe-Detmold, in Westphalia, J. L. Jacobi, conceived the idea, of 

 artificially fecundating the eggs of fish, and of applying this process to the 

 repopulatiug of ponds and rivers. The curious results of his experi- 

 ments were, indeed, embodied in a letter, which the "Magazine of Han- 

 over" only published in 1 703 ; t but as early as 1758 Jacobi had addressed 

 manuscript-notes upon the subject to the illustrious Buffon, which La- 

 cepede has mentioned in the first volume of his " Natural History of Fishes," 

 and in the course of the same year he had intrusted another account of 

 his labors to the Count de Goldstein, grand chancellor of Berg and 

 Juliers. Goldstein caused a Latin translation of it to be made, which 

 he sent M. de Fourcroy, director of fortifications at Corsica, and an 

 ancestor of the celebrated chemist. This version was published for the 

 first time in French in 1773, in vol. iii of the " General History of the Fish- 

 eries " by Duhamel-Du Monceau. Duhamel does not mention Jacobi ; but, 

 the facts in both memoirs being perfectly identical and set forth in siinilai 

 terms, it is impossible not to perceive that both writings emanate from 

 the same author. The date of the first communication entirely secures 

 the claims of Jacobi, which are besides confirmed by the quotations of 

 Lacc^'pede, and by a communication made in 17G4 by Gleditsclj to the 

 Academy of Sciences at Berlin. We give the details, because, the name 

 of Goldstein alone having been printed in the " History of the Fisheries," 

 many naturalists have wrongly attributed to him the merit of the dis- 

 covery of artificial fecundations. 



The experiments of Jacobi were upon the two most esteemed species 



*Miirc Eiitizer BJocii, General and Particular Ichthyology, part ii, p. 94, 1795. 



tit is to be found also, in extenso, in William Yarrell, History of British Fishes, vol. ii, 

 p. 87, 1841 ,* and at the end of Practical Instructions upon Pisciculture, by M. Coste, 

 1853. 



