Luminous Plants and Animals

Luminous Plants and Animals By A. O. Garrett, Professor of Botany, Alpine Summer School, Brigham Young University A YOUNG man at the Alpine Summer School at Aspen Grove chopped up some maple roots for fuel one day last summer. It had been raining for several days, and as a consequence the wood was well soaked. He happened to pass his pile of wood after dark, and found to his surprise that it was luminous in spots — wherever the bark had been broken there was a greenish glow. The combined glow was almost sufficient to permit one to read by it. This phenomenon created some interest in camp, and naturally the question followed, "What is the cause?" together with the second question, "What plants and animals are known to be luminous?" These questions are not so simple as they appear to be. If we were in the open more after nightfall, perhaps we would observe more of this luminescence from plants and animals; for the phenome- non is not so rare as the uninformed imagines. In fact, it is pretty well distributed all through organic nature. AMONG PLANT Life, we meet with it first among the bacteria — those tiny organisms so small that of the small ones it would take 125,000 placed side by side to make a line an inch long! In their General Bacteriology, Frost and McCampbell say, "Some vege- tables, such as potatoes, beans, etc., on decomposition may give off light and show the presence of phosphorescent bacteria. Decompos- ing meats, particularly sausages and fish, also may be covered with different species of phosphorescent bacteria. Fischer states that the phosphorescence of the sea is due to the growth of saprophytic photogenic bacteria on dead sea animals and the subsequent washing off of these forms in large numbers by waves." At least twenty-six species of photogenic bacteria have been discovered. (As will be seen later, the phosphorescence of the sea is due to a number of dif- ferent organisms.) Then the mycelia of certain fungi (particularly of toadstools and their allies) , which grow in rotten wood, cause what is some- times called "fox wood." This is sometimes quite common in the timbers of mines and under the bark of decaying trees. (The mycelium of a fungus is really the fungus itself — what we call the toadstool being its fruiting body only.) This was the organism which caused the luminescence at Aspen Grove. The subject of luminosity of these fungi is discussed at length in chapter V of Cooke & Berkeley's Fungi. Here the experience observed at Aspen

844 IMPROVEMENT ERA Grove is verified — that the luminosity is evident when the fungus is alive and wet, and disappears upon the plant becoming dry. Among the independent plants, one of the most interesting cases of luminosity is found in a moss that grows in dark caves. In his book, Mosses with a Hand Lens, Dr Grout says of the Luminous Moss: "The Luminous Moss belongs in a family all to itself because of its numerous peculiarities. It is found in caves and dark holes in the woods, sometimes under the roots of overturned trees. It has once been found under the sill of an old shed. On looking into one of these caverns containing the Luminous Moss, the bottom seems covered with a golden-green glow, somewhat like the appearance of a cat's eye in the dark. In order to see the glow, one must look into the cave with the light behind him and care must be taken not to shut off all the entering light, as the Luminous Moss, like the moon, shines by reflected light alone. If one attempts to gather the glowing substance he will find nothing but dirt and stones with possibly a few tiny plants. * * * The compound microscope will reveal threads, * * * but the lens will show only a cobwebby appearance of fine green threads. This beautiful plant is probably the reality upon which are based the fairy tales of goblin gold." Among Animal Life, we find many more examples than among the plants. In fact, the phenomena of luminescence in animal life extend in all the different groups of animals. In the Protozoa, or one-celled animals, a great many kinds have the power of giving forth light. In his book, The Protozoa, Gary N. Calkins says: "In the sea great areas may be colored orange, red, etc., by incalculable numbers of Noctiluca (the Protozoan best known for its phosphorescent effect) , while at night their presence is indicated by brilliant phosphorescence, the light being due to the rapid exudation of a substance created by the organisms and thrown out by them upon irritation. In Puget Sound and in Alaska I have seen hundreds of acres of the sea surface colored orange by Noctiluca militaris, although the single individuals are less than one-fiftieth of an inch in diameter." In an article entitled "The Phosphorescence of the Sea," reprinted in Vol. 1 of the American Naturalist, pages 316 and 317, the statement is made that the phosphorescence caused by the Noctilucae occurs only when the water containing the animals is agitated. Among the Coelenterates we have numerous luminous forms. The free-swimming young of the lime-secreting hydroids or Mille- pora are often brilliantly luminous. Other examples are found in the sea-anemone named Urticinia; in the single-coral polyps; and in all

LUMINOUS PLANTS AND ANIMALS 845 the Alcyonarians. The latter group includes the sea-fans, sea-pens, red coral, and especially one sea-pen found off the coast of Spain, which is noted for its luminosity. With few exceptions, all of the Marine Worms are luminous: green, blue, white and yellow light marking their movements under the sea. Among the mollusks, we find examples of luminosity in the Boring Shells. One called Pholas emits a bluish- white light; one placed in honey retained its light for over a year. Still another luminous mollusk is the sea-slug called Scyllea. A land-slug called Limax has a luminous pore on its mantle, while the eggs of another land-slug are luminous for the first fifteen days. Several of the Squids (Celodora and Cranchia) are luminous. We find abundance of luminosity among the Crustaceans. The writer observed the luminosity of the water-fleas when looking at them through the microscope on a rather dark day. Certain marine species are often responsible for the phosphorescence of the sea. Major Owen said: "When these were taken, the sea was alive with them. When swallowed by, or entangled with other creatures, they in their turn appear to be also luminous. They also give luminosity to the water itself as it flows over them. When they are at rest, they gradu- ally cease to give out light; but as soon as they are disturbed or in motion, or the vessel containing them is shaken, they again become bright, even after many hours' confinement, — I have seen the ship's deck running with liquid fire when the net containing this species was taken on board." We find another example in Idotea phosphrea of the fourteen footed Crustaceans; but perhaps the most remarkable luminous Crustacean is the little Medtridia armata, a spider-crab that "exists in such quantities in the snow on the shores of the Arctic ocean that persons and animals appear to be walking in fire, the splashes of light presenting a wonderful spectacle. The light is of a bluish-white tint." The crab known scientifically as Cancer fulgens is luminous. At least thirty-four kinds of insects are known to be luminous. Perhaps the best known of these to us is the fire-fly. A gentleman up in City Creek canyon, one day, last spring, observed the ground aglow with phosphorescence for a space of about an acre. He in- vestigated, and found the ground was literally alive with some kind of a "worm." The "worm" was the female and the young of the fire-fly, or the glow-worm. One of the most remarkable cases of luminosity is found in one of the elaters, or snapping-beetles, found in the West Indies (Elater noctilucus.) It is said that the light of a few of these insects has been used as a lantern. G. A. Perkins gives an interesting account of them in Vol. 2, of the American Naturalist: "The Cucuyo; or West Indian Fire Beetle."

846 IMPROVEMENT ERA Even the vertebrates have examples of luminous forms; for we have the Lamp-fishes, which have organs which look like pearl or glass buttons imbedded in the skin. These are luminous organs and aid the fishes to light the dark recesses of the submarine work. The entire head of another deep-sea fish (Canlolepis Longidenis) glows with a pale-green light. Still another has a tiny lantern suspended by a thread over its back. All known examples of luminosity among plants and animals have not been given; but sufficient have been mentioned to show that the question, "What plants and animals are luminous?" is one that cannot be answered in a breath. Provo, Utah. In Crowded Places Let me live in the crowded places, Midst the throng of struggling men; Let me carry my load of trouble, Helping others now and then. Let me find in the crowded places Chances to serve mankind, Till the end of life's hard battle, When we'll leave all cares behind. Let me walk in the silent places, When my soul is dull with care. Let me find sweet rest and comfort, When I kneel in secret prayer. But let me live with the masses, With the humble men of earth; For there I find great treasures, The richest joys of earth. Durango, Colo. BESSIE BURNHAM