THE ELUSIVE QUARRY 35 



Sir Herbert Maxwell, we have seen, cites a case 

 in which a salmon rising at a lure was moved 

 by desire to eat. Why does he treat it as 

 exceptional ? That, as I shall endeavour to show, 

 is a crucial question. Let us suppose that the 

 fisherman had not seen the butterfly; that simply 

 it had occurred to him that a Mayfly might prove 

 appropriate to the size of the river; and that the 

 Mayfly raised the salmon. How would Sir Herbert 

 have interpreted the incident then? Would he 

 have said that the fish rose with " gustatory intent " ? 

 It is safe to feel assured that he would not He 

 would not have perceived in the incident anything 

 to disturb his understanding that it is not in the 

 expectation of something to eat that salmon rise at 

 flies. Not knowing all, he would not have under- 

 stood all. A salmon caught on a Mayfly ! He 

 would have been more than ever confident that it 

 is not to appetite that any selection from the 

 tackle-book makes appeal. It is probable, indeed, 

 that he would have regarded the incident as a 

 dramatic proof of the theory that salmon do not 

 rise to feed. The accident of his knowing about 

 the butterfly enabled him to interpret the matter 

 truly. When, in such cases, is our knowledge 

 approximately complete? Sir Herbert Maxwell 

 would be the last to say that it is so often. The 

 most vigilant eye cannot detect all that happens 

 on even a few yards of salmon river. Reviewing 

 his successes with the fish, Sir Herbert would be 

 able in only a very few instances to be sure of what 



