NATURAL HISTORY OF THE SALMON. 63 



the facts can be said to have been publicly and formally 

 called for ; and the case must now go to proof. 



Whether a grilse (admittedly a fish of the salmon 

 genus, but smaller in size, and slightly different in ap- 

 pearance, compared with the fish everywhere acknow- 

 ledged as the true salmon) is an adolescent salmon on its 

 first ascent from the sea, or is a distinct species, compris- 

 ing, of course, both adolescent and adult fish that is the 

 question. All scientific, with almost all popular belief, 

 supports the first proposition ; Mr. Mackenzie of Dun- 

 donnell, and a few others who have not ventured upon 

 paper, maintain the second. As in most ichthyological 

 questions, especially those relating to the migratory 

 tribes, there is an insufficiency of direct evidence ; and 

 what there does exist of direct evidence we shall reserve 

 till after the leading of the circumstantial proofs. The 

 points to be dealt with relate to the habits of the fish, 

 especially as to season to the proportion that salmon 

 and grilse are found to bear to each other, both in given 

 rivers and in given years to the size or weight and to 

 the shape or appearance. What we shall adduce under 

 these heads will, we hope, be found to go almost the 

 whole way to prove that there is some sort of connexion 

 between the two kinds, or rather sizes, of fish ; and a 

 very long way to prove that the connexion or relation is 

 that of youth and adult. 



Foremost among those evidences we would place the 

 fact (already alluded to in discussing the period of the 

 fish's first return to fresh water), that salmon ascend 

 rivers more or less in every month of the year, whilst 

 grilse do not ascend at all until a certain period, and 



