Poiet.—I see you are obliged to run with him, and have carried him safely through the weeds.
Hal.—I have him now in the rapids on the shallow, and I have no fear of losing him, unless he strikes the hook out of his mouth.
Poiet.—He springs again and again.
Hal.—He is off; in one of these somersets he detached the steel, and he now leaps to celebrate his escape. We will leave this place, where there are more great fish, and return to it after a while, when the alarm produced by our operations has subsided.
Phys.—That fish take the artificial fly at all is rather surprising to me, for in its most perfect form it is but a rude imitation of nature; and from the greedy manner in which it is seized, fish, I think, cannot possess a refined sense of smell, or any nervous system corresponding to the nasal one in animals that breathe air: no scent can be given to water by an artificial fly, or, at least, none like that of the natural fly.
Hal.—The principal use of the nostrils in fishes, I believe, is to assist in the propulsion of water through the gills for performing the office of respiration, but I think there are some nerves in these organs which give fishes a sense of the qualities of the water, or of substances dissolved in, or diffused through it, similar to our sense of smell, or, perhaps, rather our sense of taste, for there can be no doubt that fishes are attracted by scented pastes and scented worms, which are sometimes used by anglers that employ ground-baits; and in old angling-books there are usually receipts for attracting fish in this manner, and though the absurdity of many of these prescriptions is manifest, yet I do not think this proves that they are entirely useless, for, upon such principles, all the remedies for diseases in the old pharmacopœias would be null.
With respect to the fly, as it usually touches the stream by a very small surface, that of the air-bubbles on the fringes on its legs, it can scarcely affect the water so as to give it any power of communicating smell. And as you have seen a ripple or motion on the water is necessary to deceive fishes; and as they look at the fly from below, they see distinctly only the legs and body, which, when the colours are like those of the natural fly, may easily deceive them; the wings, which are the worst imitated parts of the artificial fly, seldom appear to them, except through the different refractive power of the moving water and the atmosphere, and when immersed, they form masses not unlike the wings of a drowned fly, or one wetted in rising.
It is now a quarter of an hour since we left the large pool: let us return to it; I see the fish are again rising.
Poiet.—I am astonished! It appears to me that the very same fish are again feeding. There are two fish rising nearly in the same spot where they rose before: can they be the same fish?