LUMINOUS FISH. (_Chauliodus._) SILICIOUS SPONGE. LUMINOUS CORALS. LUMINOUS CRUSTACEAN. (_Ptichogaster._)] It is usually the misfortune of the single observer, or the minority, to be ridiculed, and their word doubted, simply because others do not choose to believe their statements. That such a course is unjust, is well shown in the instance of the daughter of Linnæus, who made the statement, that as she approached the flowers of _Dictamnus albus_ with a light they appeared to ignite, without, however, injury to them. This experiment was tried time and again by others, but without success; and not a few scientists of the day regarded it as a delusion, while others averred that it was pure invention; opinions which placed the lady in a disagreeable position. Some years after, Dr. Hahn was enabled to show that the experiment was not mere fiction. He says, “Being in the habit of visiting a garden in which strong, healthy plants of _Dictamnus albus_ were cultivated, I often repeated the experiment, but always without success; and I already began to doubt the correctness of the observation made by the daughter of Linnæus, when, during the dry and hot summer of 1857, I repeated the experiment once more. Fancying that the warm weather might possibly have exercised a more than ordinary effect upon the plant, I held a lighted match close to an open flower, but again without result; in bringing, however, the match close to some other blossoms, it approached a nearly faded one, and suddenly was seen a reddish, crackling, strongly shooting flame, which left a powerful aromatic smell, and did not injure the peduncle. Since then I have repeated the experiment during several seasons; and even during wet, cold summers it has always succeeded, thus clearly proving that it is not influenced by the state of the weather. In doing so, I observed the following results, which fully explain the phenomenon. On the pedicels and peduncles are a number of minute reddish-brown glands, secreting etheric oil. These glands are but little developed when the flowers begin to open, and they are fully grown shortly after the blossoms begin to fade, shrivelling up when the fruit begins to form. For this reason the experiment can succeed only at that limited period when the flowers are fading. The radius is uninjured, being too green to take fire, and because the flame runs along almost as quick as lightning, becoming extinguished at the top, and diffusing a powerful incense-like smell.”