No, in all probability, says the reader; but the opposite popular belief is supported by eminent naturalists. Buffon says: “The eyes of the cat shine in the dark somewhat like diamonds, which throw out during the night the light with which they were in a manner impregnated during the day.” Valmont de Bamare says: “The pupil of the cat is during the night still deeply imbued with the light of the day;” and again, “the eyes of the cat are during the night so imbued with light that they then appear very shining and luminous.” Spallanzani says: “The eyes of cats, polecats, and several other animals, shine in the dark like two small tapers;” and he adds that this light is phosphoric. Treviranus says: “The eyes of the cat _shine where no rays of light penetrate_; and the light must in many, if not in all, cases proceed from the eye itself.” Now, that the eyes of the cat do shine in the dark is to a certain extent true: but we have to inquire whether by _dark_ is meant the entire absence of light; and it will be found that the solution of this question will dispose of several assertions and theories which have for centuries perplexed the subject. Dr. Karl Ludwig Esser has published in Karsten’s Archives the results of an experimental inquiry on the luminous appearance of the eyes of the cat and other animals, carefully distinguishing such as evolve light from those which only reflect it. Having brought a cat into a half-darkened room, he observed from a certain direction that the cat’s eyes, when _opposite the window_, sparkled brilliantly; but in other positions the light suddenly vanished. On causing the cat to be held so as to exhibit the light, and then gradually darkening the room, the light disappeared by the time the room was made quite dark. In another experiment, a cat was placed opposite the window in a darkened room. A few rays were permitted to enter, and by adjusting the light, one or both of the cat’s eyes were made to shine. In proportion as the pupil was dilated, the eyes were brilliant. By suddenly admitting a strong glare of light into the room, the pupil contracted; and then suddenly darkening the room, the eye exhibited a small round luminous point, which enlarged as the pupil dilated. The eyes of the cat sparkle most when the animal is in a lurking position, or in a state of irritation. Indeed, the eyes of all animals, as well as of man, appear brighter when in rage than in a quiescent state, which Collins has commemorated in his Ode on the Passions: “Next Anger rushed, his eyes on fire.”