82 THE SALMON, 



a very imperfect knowledge of their proceedings, espe- 

 cially in the breeding season of spring, when the fur or 

 the plumage of old and young have in few cases much 

 visible difference. Further, salmon are migratory, and we 

 do not know the habits of migratory creatures in that 

 respect — for instance of swallows. Further yet, though 

 we must yield to Mr. Mackenzie the fact that whenever 

 a pair of fish of the salmon kind are seen together on a 

 spawning-bed, they are seen to be, with comparatively 

 rare exceptions, pretty much of the. same size; yet in the 

 water the eye is not capable of distinguishing in the 

 case of two fish, say of seven or eight pounds, whether 

 t)oth are salmon, both grilses, or one of each. Besides, 

 the fact cuts both ways, as indicating that, in the pro- 

 cess of pairing, the choice is regulated mainly hy con- 

 siderations of size, not necessarily, nor probably, by the 

 consideration as to whether any fish of the desired size 

 is on its first ascent, or at some later stage of its career 

 —whether maid or widow, bachelor or widower. All 

 that we see really proves, not that salmon and grilse, but 

 that large fish and small fish, have a dislike to form 

 matrimonial relations with each other. Finally, in the 

 experimental ponds at Stormontfield, the ova of an adult 

 female salmon were impregnated with the milt of a male 

 grilse, the ova fructified, and the progeny were undis- 

 tinguishable from those produced by two adult parents. 

 This fact, indeed, we might have made both the first and 

 the last of our replies to the allegation that grilse and 

 salmon do not breed together ; but as the point does not 

 seem to have received very much attention at those 

 admirable ponds, and as there is always a possibility of 



