NATURAL HISTORY OF BRITISH SALMONID^E. 147 



' In Holsfjard, in Ringerike, not far from Chiistiania, a lake 

 larger, I believe, than any of our Scotch or Irish lochs, several 

 thousand salmon fry has been turned in, which now have attained 

 weights varying from three to nine pounds. 



' And, now, what deductions may we at home draw from the 

 above interesting facts? Why, not only that sea trout and 

 salmon will grow in fresh water, but that they will also breed 

 there without migrating to the sea. That their development is 

 more tardy than of those which have access to salt water is 

 only what might be expected. 



' It seems further that the larger the lake the speedier their 

 growth. And this undoubtedly seems to corroborate the opinion 

 that the salt water is not absolutely essential to their develop- 

 ment; but that they grow quicker when they have access to it, 

 chiefly because they have a more varied and abundant supply 

 of food. And if one further takes into consideration that 

 salmon are as much fresh-water as sea-water fish (for their stay 

 in the former is quite as long and in some instances longer than 

 in the latter) ; and that they have also so much in common with 

 river trout and charr, it will be allowed, I think, that these 

 experiments in Norway may open a wide field for practical 

 investigation with us. 



'Another fact worthy of notice is that it was with the young 

 fry, and not with ova that the experiments were made. 



' Whether the salmon after a lapse of time will like sea trout 

 adopt the form, colour, and flavour of fresh-water trout, expe- 

 rience only can decide. 



' It seems too that while the experiments in small ponds have 

 been partial failures (though even in this case it has been shown 

 that they will breed in them), those that have been made in 

 waters of large dimensions have quite realised all reasonable 

 expectations. 



'The Nirosen lake, which ranks next in size to the 

 Wenern and Wettern, is, I hear, to be experimented on 

 on a large scale. I trust the trial will meet with the success 

 it deserves.' 



L 2 



