SALMON-FISHERY OF SCOTLAND. 47 



admit their gregarious associations, like those of herrings, and 

 yet seem to think that the gregarious instinct was implanted 

 into them for no purpose, while swimming about the shores 

 like haddocks. They tell us that they are driven into the 

 rivers by sea-lice, without adverting that the assertion is 

 utterly incompatible with the gregarious instinct, — for if the 

 lice can force individuals to leave the shoal, they must, of 

 course, overcome the gregarious instinct which keeps them 

 together. This idea of lice impelling salmon to proceed to the 

 rivers is a very absurd one. When a shoal of salmon leaves 

 its migratory abode in the ocean, in obedience to instinct, or 

 the law of its nature, to proceed to its river, it must accomplish 

 its destination, whether any of the fish of which it is composed 

 have sea-Uce or not ; yet, according to the stake-net doctrine, 

 after the shoal had reached the estuary, only those fish which 

 were infected with lice would go to the river, and the rest, after 

 amusing themselves on the banks for a little while, would 

 return back to the sea, unless intercepted by them, — though 

 every fish they take is just as much infested with these 

 lice as those which are taken at the rivers. The whole of their 

 arguments, indeed, form one mass of inconsistency and absurd- 

 ity. They will, perhaps, next teU us, that the migratory birds 

 are sent to us by vermin, and not in consequence of instincts 

 connected with the migratory system, — and that when a migra- 

 tory flight reaches our coast, the whole tribe is not actuated by 

 the same instinct, but Kke salmon, have different and even 

 opposite instincts ; some of them having the instinct of re- 

 maining, while others, on the contrary, after they reach our 

 shores, set off again immediately to whence they came, just 

 according as they were, more or less, troubled with lice. 



Suppose we were to put the following questions to Mr 

 Halliday : — ^You say that the salmon are driven into the rivers 

 by lice. — Who told the salmon that fresh water was a cure ? 

 How did you discover that salmon knew, or have found out this 

 secret ? Did a seal tell you so ? Why did not the salmon 

 taken in your stake-nets, all of which had lice upon them, go 

 also to the rivers ? You say you intercepted them returning to 

 the sea, — were they carrying back their lice to the sea with 



