It is pleasant, rod in hand, on a breezy spring day, while trying to coax “the monarch of the brook” from his sheltering pool, to watch this annual migration, and to note the passage of the bright-mailed army adown the majestic river, that hurries on by busy corn-mill and sweeps with a murmuring sound past hoar and ruined towers, washing the pleasant lawns of country magnates or laving the cowslips on the village meadow, and as it rolls ceaselessly ocean-ward, giving a more picturesque aspect to the quaint agricultural villages and farm homesteads which it passes in its course. During the whole length of its pilgrimage the army of smolts pays a tribute to its enemies in gradual decimation: it is attacked at every point of vantage; at one place the smolts are taken prisoners by the hundred in some well-contrived net, at another picked off singly by some juvenile angler. The smolt is greedily devoured by the trout, the pike, and various other enemies, which lie constantly in waiting for it, sure of a rich feast at this annually-recurring migration. But the giant and fierce battle which this infantile tribe has to fight is at the point where the salt water begins to mingle with the stream, where are assembled hosts of greedy monsters of the sea of all shapes and sizes, from the porpoise and seal down to the young coal-fish, who dart with inconceivable rapidity upon the defenceless shoal and play havoc with the numbers. Many naturalists dispute most lustily the assertion that the smolt returns to the parental waters as a grilse the same year that it visits the sea; and some writers have maintained that the young fish makes a grand tour to the North Pole before it makes up its mind to “hark back.” It has been pretty well proved, however, that the grilse may have been the young smolt of the same year. A most remarkable fact in the history of grilse is, that we kill them in thousands before they have an opportunity of perpetuating their kind; indeed on some rivers the annual slaughter of grilse is so enormous as palpably to affect the “takes” of the big fish. It has been asserted, likewise, that the grilse is a distinct fish, and not the young of the salmon in its early stage. There has been a controversy as to the rate at which the salmon increases in weight; and there have been numerous disputes about what its instinct had taught it to “eat, drink, and avoid.”