218 THE PRACTICAL FISHERMAN. 



some insects, such, for instance, as the ant, consist largely of formic 

 acid. However this may be, it is certain that the most fattening food 

 for tame trout is not that which is artificially prepared. 



The question has been raised as to the possibility of the non-migratory 

 trout living in salt water. I can confidently assert that they will, for 

 sometime ago there was a good Salmo fario living with some smelts in 

 salt water at the Brighton Aquarium. Mr. Lawler (the naturalist) told 

 me it did not appear so lively as in fresh water, but that during its 

 confinement it grew, and it fed voraciously. The tints of the fish appeared 

 to have become brighter. 



The longevity of trout, like that of any animal, is diflicult to pro- 

 nounce upon. A farmer near Pontypool is said to have kept one in 

 captivity twenty-seven years, during which time it had not increased in 

 size. Daniel, in the supplement to his " Rural Sports," speaks of one 

 living twenty-eight years in a well at Dumbarton Castle, and Yarrell 

 refers to one said to have existed fifty-three years at Broughton-in- 

 Furness. The probable age to which Thames trout attain is from fifteen 

 to twenty years. 



The gillaroo, or gizzard, trout has been " hastily " (according to Pennell) 

 named as a different species of trout. I do not think that there has been 

 much hastiness in the proceeding, seeing that Davey, Yarrell, and Couch 

 name its differences from the 8. fario in detail, and each appears to regard 

 its identity as completely differing from that of the true brook trout. 

 That the differences I shall recapitulate really do exist there can be no 

 doubt, but it may be a question whether they are of sufficient importance 

 to elevate a variety into a species. 



Sir Humphrey Davey, in " Salmonia," refers to it at length, and, 

 from what he says, it seems that in appearance it differs from the 

 S. fario, in that it has more red spots and a yellow or golden coloured 

 body and fins, and generally presents a thicker and more robust appear- 

 ance. The stomach is the feature which has attracted attention and 

 gained a separate name. Its form has been improperly likened to that of a 

 fowl's "gizzard" the consistence of which, being very thick as com- 

 pared to that of the organ in other fishes, has given it the prominence 

 referred to. "If it be the common trout, after all," Sir Humphrey says, 

 "they have been altered in successive generations." 



The great anatomist, John Hunter, distinguishes the stomach of this 

 fish from the "gizzard" of poultry, since it wants some of the powers 

 with which that organ seems chiefly endowed. For example, it has no 

 bony cuticle, and thus the grinding qualities of a gizzard are not given it. 

 Its capacity is circumscribed, however, as compared with other fish, 

 and it has been conjectured that this is for the purpose of facilitating 



