SHAW'S EXPERIMENTS. 131 



change took place from the parr to the smolt. The late Mr. 

 Yoijng of Invershin, a well-known authority on salmon life, was 

 experimenting at the same time as Mr. Shaw, and for the 

 same purpose-^namely, to determine if parr were young salmon, 

 and, if so, at what period they became smolts and proceeded 

 to the sea. Mr. Shaw said two years, and Mr. Young, who 

 was then manager of the Duke of Sutherland's fisheries, 

 said the change took place in twelve months ; others, again, 

 who took an interest in the controversy, said that three years 

 elapsed before the change was made. The various parties 

 interested held each their own opinion, and it may even be 

 said that the disputation still goes on ; for although a numer- 

 ous array of facts bearing on the migration have been gathered, 

 we are stUl in ignorance of any regulating principle on which 

 the migratory change is based, or to account for the impulse 

 which impels a brood of fish to proceed to sea divided into 

 two moieties. Mr. Shaw watched his young' fry with un- 

 ceasing care, and described their growth with great minute- 

 ness, for a period extending over two years, when his parrs 

 became smolts. Mr. Young, in a letter from Invershin, dated 

 January 1853, says, pointedly enough— "The fry remain in 

 the river one whole year, from ihe time they are hatched to 

 the time they assume their silvery coat and take their first 

 departure for the sea. All the experiments we have made on 

 the ova and fry of the salmon have exactly corresponded to the 

 same effects, and none of them have taken longer in arriving at 

 the smolt than the first year." 



The late Mr. Buist, in one of his letters on the progress of 

 artificial breeding at the Stormontfield ponds, says : " There is 

 at present a mystery as regards the progress of the youi^ 

 salmon. There can be no doubt that all in our ponds are really 

 and truly the ofispring of salmon ; no other fish, not even the 

 seed of them, could by any possibility get into the ponds. Now 

 we see that about one half have gone off as smolts, returning in 

 their season as grilses ; the other half remain as parrs, and the 

 mUt in the males is as much developed, in proportion to the 

 size of the fish, as their brethren of the same age seven to ten 

 pounds weight, whilst these same parrs in the ponds do not 

 exceed one ounce in weight. This is an anomaly in nature 

 which I fear cannot be cleared up at present. I hope, however, 

 by proper attention, some light may be thrown upon it from our 

 experiments next spring. The female parrs in the pond have 



