542 SUPPLEMENT ON 



and perhaps of nutriment. This faculty renders it rarely- 

 necessary to replenish the ponds which have been fished, 

 as a sufficient quantity of eels generally remains concealed 

 to answer the purpose of re-stocking them as soon as the 

 water has been restored. 



The eels live on small fish, on the spawn of large ones, 

 on insects, on carcases in a state of decomposition which have 

 been thrown into the water, and even, as has already been 

 mentioned, on vegetable substances. They are very vora- 

 cious, and digest their prey very rapidly ; accordingly, they 

 must not be suffered to multiply too fast in ponds, if it be 

 desired to maintain there an abundance of other fishes. 



Volumes have been written respecting the mode of re- 

 production of the eels. Aristotle believed that they sprang 

 from the mud ; Pliny from fragments which they separated 

 from their bodies, by rubbing them against the rocks ; other 

 ancients supposed that they sprang from the carcases of ani- 

 mals ; Helmont believed that they came from May-dew ; 

 Schewenckfield from the gills of a cyprinus; others supposed 

 them to come from the cod, whiting, &c. Spallanzani him- 

 self maintains that thousands of eels have been fished in the 

 lakes of Italy, without either eggs or foetus being found in 

 their body, and he supposes that they procreate only in the 

 sea, without paying attention to the fact, that a large portion 

 of these fish never go voluntarily, and even most frequently 

 cannot go into salt water. The truth is, that the eels couple 

 after the manner of serpents, as has been witnessed by Ron- 

 delet ; that they form eggs, which, for the most part, disclose 

 in their belly ; and that in this case they are viviparous, after 

 the manner of the vipers. 



Lacepede, in his Natural History of Fishes, quotes some 

 observations of Sept. Fontaines, in illustration of this fact, and 

 our countryman, Mr. Yarrell, has lately investigated the sub- 

 ject with his usual ability and success. 



