“You have very often seen frogs and toads in the water, and no doubt you think they could live there indefinitely. Undeceive yourselves: they go to the water only to lay their eggs or to escape from some danger or to bathe in hot weather, but they could not remain under water any length of time without dying. They have to come up at intervals to breathe, which they do by getting at least the nostrils out. Here we have a difference between the tadpole and the full-grown batrachian, between the larva, so to speak, and the creature at its maturity: the tadpole lives in water and perishes in the air, whereas the frog that comes from it lives in the air and perishes in water. “And there is a still further difference: the tadpole lives exclusively on vegetable matter, its mouth is equipped with a sort of small horny beak to browse the foliage of water-plants, and in its big belly it has a very long intestine coiled about several times so as to prolong the passage of the food through the body and thus make sure that all the juices it may contain are extracted. The mature batrachian exchanges this horny beak for real jaws furnished with irregularities that serve as teeth, it lives solely on an animal diet, especially on insects, and its intestine is short because the food it eats is easy of digestion and readily yields what nourishment it contains. “To turn a tadpole into a frog or a toad it is not enough to change its respiratory and digestive organs; new organs form, organs of which there was not the least sign when the creature was hatched, while still others disappear without leaving any trace. The tadpole is born absolutely without legs. After a while the hind legs appear, later come the fore legs, and still later the tail shrinks and vanishes.” “I remember seeing tadpoles,” said Jules, “some with two legs, some with four; but every one of them had a tail.” “When the tail has disappeared the animal is no longer a tadpole, but a young toad or frog.” “Does the tail come off itself, or does the animal pull it off?” Emile inquired with eager interest.