210 Dr. Mac Culloch on the changing 



interesting nature, concern the means of transferring the inhabi- 

 tants of fresh waters in one country, or those of certain lakes or 

 rivers, to others where they are not found, some hints are also 

 introduced respecting the possibility of rendering certain sea-fish in- 

 habitants of fresh waters. The whole paper is highly worthy of 

 attention ; but I am not aware that it has been followed by any of the 

 practical trials recommended by the author, on which its economical 

 value must ultimately depend. An example in point which recently 

 came under my notice in Shetland, has induced me to examine the 

 subject with somewhat more care than the author of that memoir 

 seems to have bestowed on it, and to inquire more minutely into the 

 arguments on which the probability of success rests. The following 

 seem to be the only results which have been obtained, or were pre- 

 viously known with respect to that part of M. Nouel's plan, which 

 relates to the cultivation of sea-fish in fresh water. 



The plaice, Pleuronectes Platessa^ as it appears, has been carried 

 from the North sea to the ponds of East Friesland, where it has 

 become established. The herring is said by Liancourt to frequent 

 the Potowmack, Hudson, Elk, and Delaware rivers ; but it has not 

 appeared that the author's project to take it from the Seine into 

 fresh-water ponds has been put into practice. The authority of 

 Twiss for the existence of this fish in the fresh water lakes of Ire- 

 land, is more than questionable, and M. Nouel is assuredly misin- 

 formed when he states that it is found in prodigious shoals in Loch 

 Lomond and Loch Eck in Scotland, both of them fresh inland 

 lakes. I know not how this author can have thus been misled, 

 unless he has mistaken some of the sea lochs for fresh-water lakes ; 

 though he could scarcely have confounded those he has named 

 with any of the western inlets. I shall hereafter, however, point 

 out a factfwhich renders his assertion possible; though he could not 

 have been acquainted with it, as it is not very long since it was 

 known, and has not been published in any work likely to have 

 reached his hands. 



It is also asserted in the same paper, that the salmon, in Scotland, 

 has, in certain lakes, become naturalized, " abandoning their erra- 

 tic taste, for a calm and settled life." Whether such an experiment 



