“Where are all our frogs?” asked Hermie. “Frogs hibernate,” I said. “As winter closes in they bury themselves in masses in the mud under the water. Some degree of moisture is needful to them at all times, and the mud affords all the dampness and warmth necessary. If the pond dries away, and the mud hardens about them, so that they cannot get out, they may live in their imprisonment for a number of months.” “I have heard,” said Hermie, “that frogs have lived shut up in lumps of coal, in rocks, and in trees, for a great many years. Do you believe that?” “I should want more reliable witnesses and more accurate information than have ever yet appeared in behalf of these tales. Experiments have shown that frogs and toads soon die if entirely shut away from air and food, though with a very little air and food they can live a long time shut up in wood or clay. An old man told me he had seen a frog taken out of a rock, where it had been buried five hundred years, and when it came out it _howled_. Now I know that a frog cannot howl,[63] and I concluded that one part of this marvellous tale was as untrue as the other.” The frogs, whose scientific name is Ranidæ, belong to the lower vertebrates, and are the largest family of their order. They are scarcely known in Australia and South America, and reach their highest state in the East Indies. Among the best known of the Ranidæ in England and North America is the bull-frog, noted for his large size, his noisy voice, his green coat laced with gold, and his silvery vest. The most curious forms of frogs are found in South America. The Oceanic Islands usually have very few examples of the order. Frogs can endure great changes of heat and cold, and can live on land as well as in water, provided they have the amount of moisture needed to preserve the suppleness of the skin; but salt water is fatal to the frog in any stage of its existence. For the study of the Ranidæ let us return to the representative best known to us, the lusty croaker of the summer pond. The frog dressed in green, silver, bronze, and gold is an expert swimmer, a mighty leaper, an ear-splitting vocalist, aquatic in his tastes, never wandering far from his native pond except when sent to market, and thence served up at the table as a dainty. But on the table we should not know him for our frog; only his hind quarters appear, and these skinned and fried are much like the legs of a spring chicken. A most harmless, timid, and interesting beastie is the frog, and often most unfortunate, being considered a legitimate mark for all the stones that can be thrown at him by urchins wandering around his native pool. Moreover, he is filled with mortal terror when with stately progress a swan or a goose sails over the water or searches in the herbage where he hides.