EARTHWORM STUDIES.
By the Rev. Hilderic Friend,
Author of 'Flowers and Flower-Lore.'
III. Phosphorescence and Luminosity.
Among the various members of the Animal Kingdom which possess the power of emitting a phosphorescent glow are certain inhabitants of Wormland, to some of which we wish to draw attention. The notice of the public, so far as my researches show, was first directed to the subject in the year 1670 by Grimm; but scientific observation was then scarcely known. Later came Flauguergues in 1780; his paper on the phosphorescent light of Earthworms appearing in 'Lichtenberg's Magazin' in the German language. It may also be seen under the French title "Sur la Phosphorésine des Vers de terre" in 'Rozier Journ. de Phys.,' xvi. (1780) pp. 311–313. In 1873 Cohn's observations on the same subject were published in the 'Zeitschrift fur Wissenschaft. Zoologie,' vol. xxiii. pp. 459–461, and entitled "Leuchtende Regenwürmer"; while numerous recent writers have further contributed to our knowledge, especially in relation to the continental species. Thus in 1872 an article appeared in the French 'Ann. Sci. Nat.' ser. 5, t. xvi. by Panceri, entitled "Etudes sur la phosphorescence des animaux marins," in which he states that the luminosity observed in the case of certain worms is due to a secretion from the girdle where special glands exist, and that with the evolution of light there was no perceptible raising of the temperature. In this respect, therefore, the glow corresponds with that emitted by the Firefly, Noctiluca, and Glowworm. One investigator at least has tested the colour and composition of the luminosity by the spectroscope, and says that it is not unicolored or monochromatic, but compounded chiefly of the red and violet rays. Other students regard the substance which produces the light as homogeneous.
