“Well, now, Mr. Dunbar, won’t you go on and tell us what you promised?”
“What was it? I have quite forgotten.”
“Why, you said you had been led to suspect that your fish—the kind that takes wing and flies away into the bushes—had a sense of taste. Did you mean to imply that fishes generally have no such sense?”
“Yes, certainly. There are very few fishes that have capacity of taste. They have no need of it, as they bolt their food whole, and usually alive. There are curious exceptions, and—”
“But, Mr. Dunbar,” interrupted Tom, “is it only because they swallow their food whole that you think they have no sense of taste? Is there any more certain way of finding out?”
“Yes, of course. The sense of taste is located in certain nerves, called for that reason ‘gustatory nerves,’ or ‘taste goblets.’ Now, as the fishes generally have no gustatory nerves or taste goblets, we know positively that they do not and cannot taste their food. That is definite; but the other reason I gave is sufficient in itself to settle the matter. The gustatory nerves cannot taste any substance until it is partially dissolved and brought into contact with them in its dissolved state. You can test that for yourself by placing a dry lump of sugar in your mouth. Until the saliva begins to dissolve it you can no more recognize any taste in it than in a similar lump of marble.”
“But why do they eat so voraciously then? What pleasure do they find in it?” asked Dick.
“Chiefly the pleasure of distending the stomach, but there is also the natural craving of every living organism for sustenance, without which it must suffer and die. That craving for sustenance is ordinarily satisfied only by eating, but it may be satisfied in other ways. Sometimes a man cannot swallow because of an obstruction in the canal by which food reaches the stomach. In such cases the surgeons insert a tube through the walls of the body and introduce food directly into the stomach. That satisfies the desire for sustenance, though the patient has not tasted anything. When a fish takes a run and jump at a minnow and swallows it whole at a gulp, he is doing for himself much the same thing that the surgeon does for his patient.”
“But, Mr. Dunbar,” Tom asked, “why is it then that the same species of fish will take a particular kind of bait at one time of year and won’t touch it at other times? In the very early spring I’ve caught lots of perch on worms, while a little later they would take nothing but live bait, and still later, when they were feeding on insects on the surface, I’ve known them to nose even live bait out of their way, refusing to take anything but the insects. If they don’t taste their food, why do they behave in that way?”
“Frankly, I don’t know,” Dunbar answered. “I have formed many conjectures on the subject, but all of them are unsatisfactory. Perhaps somebody will solve the riddle some day, but at present I confess I can’t answer it.”