348 MR YOUNG ON THE GROWTH OF GRILSE AND SALMON. 



first change, and the migration of the smolts towards the sea. They return 

 as grilse during the summer and autumn of the same season, their increase of 

 size depending on the length of time which has elapsed between their departure 

 from and return towards the river water. Such of these grilse as escape the 

 snares of the fishermen and other enemies, spawn that same season in common 

 with the salmon, and after spawning, both the one and the other redescend into 

 the sea in the course of the winter or ensuing spring. They all return again to 

 the rivers sooner or later, according as they had previously left it, after having 

 spawned, early or late. The grilse have now become salmon by the time of their 

 second ascent from the sea All these changes and conditions I have verified by 

 special experiment, as well as by general observation, from the egg to the smolt 

 (the parr inclusive), from the smolt to the grilse, from the grilse to the salmon ; 

 and I am perfectly satisfied with the accuracy of the conclusions come to, and 

 which I have here endeavoured to explain. 



