122 SALMON-FISHEKY OP SCOTLAND. 



at the fish taken at the same place, and collected together in a 

 boat." 



" How do you account for individuals of the same species differing 

 in form 1 ?" "Precisely as individual differences are accounted for in 

 other species of animals. Salmon are exposed, in their young state, 

 to very different circumstances. Some are longer in the river after 

 having left their spawning-beds than others and it may be supposed, 

 likewise, that during their residence in the sea they may have access 

 to different quantities and different qualities of food. In fact, the 

 ordinary circumstances that produce varieties in other individuals of 

 other species, I should think likely to exist and produce individual 

 differences in the salmon." 



Having admitted that there are different BEEEDS belonging 

 to different rivers, we should think that it would be more con- 

 sonant with the Doctor's sagacity, and to common sense, to 

 impute the difference of form to that circumstance. If he saw 

 salmon of different shapes collected in a boat in the Tay, he 

 might have concluded that they were the fish of the Earne and 

 of the Tay itself, and its different branches or tributary streams, 

 which we suppose was the fact ; but to impute difference of 

 form to difference of feeding, was, of all reasons, the most 

 absurd. Difference of feeding may increase the size or improve 

 the condition of an animal ; but how can it alter its form or 

 shape I How could it make the whole of the salmon of one 

 river, uniformly, and year after year, round or hog-backed, and 

 others straight-backed? Would difference of feeding give a 

 dray-horse the symmetry of a race-horse, or a mastiff the shape 

 of a greyhound ? We would recommend to the Doctor to keep 

 this in view when he writes his next book on natural history. 



The Committee ask the Doctor why he considers the grilse 

 to be the young salmon, and not a distinct variety of the 

 species ? and he answers, with his usual tone of science, 



' ' Fish are known to breed long before they arrive at maturity ; 

 and as a proof that they do, it may be. stated, that at the end of the 

 season the salmon caught in a state fit for spawning are by no means 

 of the same size ; if, then, we are to take size as an index of aye, we 

 must arrive at the conclusion that salmon spawn at different ages, 

 and before they have reached their full size." 



We have all along thought that the Doctor's knowledge of 



