230 SALMONTA. 



There are eels in the Lake of Neufchatel, 

 which communicates by a stream with the 

 Rhine; but there are none in the Leman Lake, 

 because the Rhone makes a subterraneous fall 

 below Geneva ; and though small eels can 

 pass by moss or mount rocks, they cannot 

 penetrate limestone, or move against a rapid 

 descending current of water, passing, as it 

 were, through a pipe. Again : no eels mount 

 the Danube from the Black Sea; and there 

 are none found in the great extent of lakes, 

 swamps, and rivers communicating with the 

 Danube, though some of these lakes and 

 morasses are wonderfully fitted for them, and 

 though they are found abundantly in the same 

 countries, in lakes and rivers connected with 

 the ocean and the Mediterranean. Yet, when 

 brought into confined water in the Danube, 

 they fatten and thrive there. As to the in- 

 stinct, which leads young eels to seek fresh 

 water, it is difficult to reason : probably they 

 prefer warmth, and, swimming at the surface 

 in the early summer, find the lighter water 

 warmer, and likewise containing more insects, 

 and so pursue the courses of fresh water, as 



