- [Footnote: Lampyrides and Elaterides, in the German and Italian glow-*worms,
and in the South American Cucuyo which lives on the sugar-cane), only a consequence of the first electric discharge, or is it simply dependent on chemical mixture? The shining of insects surrounded by air has doubtless other physiological causes than those which occasion the luminosity of inhabitants of the water, fishes, Medusæ, and Infusoria. The small Infusoria of the ocean, being surrounded by strata of salt water which is a good conducting fluid, must be capable of an enormous electric tension of their light-flashing organs to enable them to shine so intensely in the water. They strike like Torpedos, Gymnoti, and the Tremola of the Nile, through the stratum of water; while electric fishes, in connexion with the galvanic circuit, decompose water and impart magnetism to steel bars, as I showed more than half a century ago (Versuche über die gereizte Muskel- und Nervenfaser, Bd. i. S. 438-441, and see also Obs. de Zoologie et d'Anatomie comparée, vol. i. p. 84); and as John Davy has since confirmed (Phil. Trans, for 1834, Part ii. p. 545-547), do not pass a flash through the smallest intervening stratum.
The considerations which have been developed make it probable that it is one and the same process which operates in the smallest living organic creatures, so minute that they are not perceived by the naked eye,—in the combats of the serpent-like gymnoti,—in flashing luminous infusoria which raise the phosphorescence of the sea to such a degree of brilliancy;—as well as in the thunder-*cloud, and in the auroral, terrestrial, or polar light (silent]*
