CULTIVATE EELS AND FROGS. 353 



sands of eels are thus annually gathered and cured for mar- 

 ket, because there is a greater number of fresh eels than is 

 necessary to supply the markets of Italy. 



At the commencement of the decade of the eighteenth cen- 

 tury the brilliant discoveries of Spallanzani enriched the nat- 

 ural sciences, and proved beyond reasonable doubt the possi- 

 bility of developing the mysteries which theorists had from 

 time to time mooted, of impregnating the eggs of fishes arti- 

 ficially. He therefore took eggs of a frog, and impregnated 

 them with the semen of a male frog. This he did before nu- 

 merous witnesses, who saw the live frogs, and saw that from 

 these eggs young frogs were hatched, and the triumph of the 

 illustrious Italian naturalist was thus rendered complete. 



In 1763 Lieut. Jacobi announced through a journal of Han- 

 over the feasibility of the artificial fecundation of salmon 

 and trout. Before, however, publishing his successful exper- 

 iments, he endeavored to promulgate his discovery through 

 the medium of celebrated naturalists, such as Buffon,De Four- 

 croy, and Gleditch, an eminent professor of Germany. " Les 

 savants" of France appeared too much preoccupied to notice 

 the Hanoverian lieutenant, especially as his writings were in 

 German. Gleditch, who was not influenced by the same rea- 

 sons, appeared impressed with the work of Jacobi, and he com- 

 municated extracts from the work to the Academy of Berlin 

 through Baron Yon Harbke. 



In France the experiences relative to the artificial fecunda- 

 tion of fishes occurred some years later. The work of Jacobi 

 was published in Paris in 1770. The Marquis de Pezay,\n 

 his Soirees helvetiennes, signalized the fortunate results ob- 

 tained at Noterlem, including the information that England 

 wished to recompense Jacobi by a liberal pension. 



Two years thereafter, and twelve years after the successful 

 experiments of Jacobi, Adamson, in his course at the Jardin 

 du Eoi in 1772, made known to his auditors the plan and 

 practicability of artificial fecundation, stating that it was ha- 

 bitually practiced on .the borders of the Weser, in Switzer- 



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