INTRODUCTION. XXXI 



prcgnated and deposited in the open gravel, or of what was 

 spawned by the fish themselves naturally. But so far as 

 could be judged, they succeeded equally well with that in the 

 baskets. Perhaps the baskets may have a preference over the 

 other methods tried, as affording more certain protection to 

 the spawn during winter ; and it is right to state that the last 

 described mode of depositing the ova and milt was most suc- 

 cessful. 



" There can be no doubt, from the success which has at- 

 tended the above-described experiments, that the breeding of 

 Salmon, or other fish, in large quantities, is, comparatively 

 speaking, easy, and that millions may be produced, protected 

 from every danger, and turned out into their natural element 

 at the proper age, which Mr. Shaw has proved by repeated 

 experiments on a small scale to be when they have attained 

 about two years of age, when the Parr marks disappear ; they 

 assume the silvery scales of their parents, and distinctly show 

 a strong desire to escape from confinement, and proceed 

 downwards towards the sea. 



" Professor Agassiz asserts, and Sir Francis fully believes 

 with truth, that the ova of all fish, if properly impregnated, 

 can be conveyed in water of a proper temperature even across 

 the Atlantic, as safely as if it were naturally deposited by the 

 parent fish, so that any quantity of Salmon, or other spawn, 

 can, after impregnation on the banks of a river, be carried to 

 other streams, however distant, which may be favourable for 

 hatching. It is right to observe that as the fry are to remain 

 two years in the artificial pools where hatched, fresh places 

 must be used every second season for the spawn, as even one- 

 year old fry will destroy spawn, or their more infantile bre- 

 thren, if left together. Old spent Salmon are also destructive 

 to both spawn and fry. 



" It can only be ascertained by experience what kind or 

 quantity of food will be required for the fry. Carrion hung 



