garding it as the sunbeam's chief constituent. Light is of the highest importance to the health and well-being of animals, as may be inferred from the fact that animal life ceases in situations from which light is totally excluded. The case of the Proteus anguinus is exceptional, and therefore deserves some notice.
This extraordinary little creature is found in some of the gloomy caverns of Illyria, into which the magic sunbeam never penetrates. "At first view," says Sir Humphry Davy, "you might suppose this animal to be a lizard, but it has the motions of a fish. Its head, and the lower part of its body, and its tail, bear a strong resemblance to those of the eel; but it has no fins, and its curious bronchial organs are not like the gills of fishes. They form a singular vascular structure, almost like a crest, round the throat, which may be removed without occasioning the death of the animal, who is likewise furnished with lungs. With this double apparatus for supplying air to the blood, it can live either below or above the surface of the water. Its fore feet resemble hands, but they have only three claws or fingers, and are too feeble to be of use in grasping or supporting the weight of the animal. The hinder feet have only two claws or toes, which in the larger specimens are found so imperfect as to be almost obliterated. It has small points in place of eyes, as if to preserve the analogy of nature. It is of a fleshy whiteness and transparency in its
