Hal.—There are instances quite as extraordinary—but I will not dwell upon them, as I am not quite sure of the fact which we are discussing; I have made a guess only, and we must observe more minutely to establish it; it may be even as you suppose—a mere dream.
Poiet.—I shall go and look at the fall: I am really satiated with sport; this is the twentieth fish I have taken in an hour, and it is a grayling of at least fifteen inches long; and there is a trout of eighteen, and several salmon trout, which look as if they had run from the sea.
Hal.—These salmon trout have run from a sea, but not from a salt sea; they are fish of the Traun See, as it is called by the Germans, or Traun Lake, which is emptied by this river.
Phys.—Tell us why they are so different from the river trout, or why there should be two species or varieties in the same water.
Hal.—Your question is a difficult one, and it has already been referred to in a former conversation; but I shall repeat what I stated before,—that qualities occasioned by food, peculiarities of water, &c. are transmitted to the offspring, and produce varieties which retain their characters as long as they are exposed to the same circumstances, and only slowly lose them. Plenty of good food gives a silvery colour and round form to fish, and the offspring retain these characters. Feeding much on larvæ and on shell-fish thickens the stomach, and gives a brighter yellow to the belly and fins, which become hereditary characters. Even these smallest salmon trout have green backs, only black spots, and silvery bellies; from which it is evident, that they are the offspring of lake trout, or lachs forelle, as it is called by the Germans; whilst the river trout, even when 4 or 5lbs., as we see in one of these fish, though in excellent season, have red spots.—But why that exclamation?
Poiet.—What an immense fish! There he is!
Hal.—I see nothing.
Poet.—At the edge of the pool, below the fall, I saw a fish, at least two or three feet long, rising with great violence in the water, as if in the pursuit of small fish; and at the same time I saw two or three minnows or bleaks jump out of the water. What fish is it?—a trout? It appeared to me too long and too slender for a trout, and had more the character of a pike;—yet it followed, and did not, like a pike, make a single dart.
Hal.—I see him: it is neither a pike nor a trout, but a fish which I have been some time hoping and expecting to see here, below the fall—a salmo hucho, or huchen. I am delighted, that you have an opportunity of seeing this curious fish, and of observing his habits. I hope we shall catch him.
Poiet.—Catch him! we have no tackle strong enough.