192 SALMON. 



intervals of a year or two, and in some instances at an unusual 

 season of the year. Fulness of habit or plumpness, or repletion, 

 has certainly an important bearing on the spring and summer 

 tendency to emigration, independent of the merely sexual 

 impulse; and it is one effect of fresh water that the excess is 

 soon abated, even when that water is of the purest kind: but 

 when soiled Avith what flows from mines of copper and lead, 

 it is so offensive not to say fatal, that these fish soon learn to 

 seek safety in other haunts. Such is the case when the stream 

 is polluted with what flows from some manufactories; and it 

 was shewn by evidence before a Committee of Parliament, that 

 where a river has become foul from tar or coal-gas, the flesh 

 of a Salmon caught in it has become so infected — although the 

 fish itself did not appear to be out of health — that even the 

 smell from it was offensive at the table. 



An interesting portion of the history of the Salmon is con- 

 nected with the attempts which have been made to propagate 

 it by artificial means; which consist in obtaining the roe from 

 beds in the river in which it had been shed spontaneously; or 

 by pressing from the living fish the roe and milt, and placing 

 them in pools of running water prepared for the purpose. They 

 become developed, and the young are fed with prepared food, 

 chiefly animal liver reduced to pulp, until they are ready to 

 emigrate to the sea. It is by these means that several rivers 

 which had been overfished and obstructed, and thus robbed of 

 their native inhabitants, have recovered what they had lost; and 

 in pursuit of what we must thus denominate an experiment, a 

 considerable amount of knowledge has been thus acquired of 

 the nature of the Salmon, where we were before altogether 

 ignorant The practice began in France by the ingenuity of 

 two humble fishermen, named Gehin and E-emy, of an obscure 

 village called I^a Bresse in the Department of Vosges, and 

 they first applied it to the propagation of Trout. The subject 

 was presently taken up by the Government of that country; but 

 it was made known among ourselves by one who wrote under 

 the name of Piscarius; since which it has been adopted among 

 us with success. Much effort has also been exerted to convey 

 the Salmon to the British Colonies, in the southern hemisphere, 

 and especially to Tasmania; whither the eggs have been con- 

 veyed, enclosed in ice, and with so much success as is implied 



