68 SENSE OF SMELL IN FISH. 



so long as to become stale, would never induce a 

 single fish to take it, although to the eye there was 

 no difference in its appearance. Again, as an experi- 

 ment, I have purposely set night-lines in the middle 

 of dense masses of weed, and in some instances in the 

 centre of a bunch of rushes, with lines all around them 

 in the open water, baited with trouts a little stale (but 

 only to be discovered by the smell), in a back water of 

 the Till, where those fish were rather numerous, and 

 invariably I found the fresh bait taken in the morning, 

 however impossible it was for it to be seen by a fish 

 passing within a few inches of it ; while the stale baits 

 in the open water, though easily seen at some distance, 

 were as invariably left untouched. To assume then 

 that the eye of the pike was capable of detecting any 

 change in the appearance of the bait, in the middle of 

 a dark night, which the keenest-sighted sportsman could 

 not discern in open day, is simply preposterous. 



To a certain extent, crepuscular vision may materially 

 aid in their nocturnal prowls in search of food, especially 

 during moonlight, or when the night is not very dark ; 

 but it is not possible to suppose that any amount of 

 crepuscular vision could enable the eels to see the worms 

 deposited in the river half a mile above them, the pike to 

 discover a trout concealed in the middle of a weed-bed or 

 bush of rushes, or to discriminate between one newly 

 caught, and another in an incipient stage of decomposition. 



Crepuscular eyes can only collect and condense what 

 feeble and scattered rays may be diffused around ; they 

 cannot create light, nor discern objects in total darkness, 



