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Show 264 PHYSIOGNOMY OF PLANTS. through the stratum of water; while electric fishes, in connection with the galvanic circuit, decompose water and impart magnetism to steel bars, as I showed more than half a century ago (V ersuche iiber die gereitze Muskel-und Nervenfaser, bd. i. s. 438-441, and see also Obs. de Zoologie et d' Anatomie comparee, vol. i. p. 84); and as .John Davy has since confirmed (Phil. Trans. for 1834, Part ii. pp. 545-54 7), 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 magnetic lightnings), which, as the result of an increased tension in. the interior of the globe, are announced for hours beforehand by the suddenly altered movements of the magnetic needle. (See my letter to the Editor of the Annalen der Physik und Chemie, bd. xxxvii. 1836, s. 242-244.) Sometimes one cannot, even with high magnifying powers, discern any animalcules in the luminous water; and yet, whenever the wave strikes and breaks in foam against a hard body, a light is seen to flash. In such case, the cause of the phenomenon probably consists in the decaying animal fibres, which are disseminated in immense abundance throughout the body of water. If this luminous water is filtered through fine and closely woven cloths, these little fibres and membranes are separated in the shape of shining points. When we bathed at Cumana in the waters of the Gulf of Cariaco, and afterwards lingered awhile on the solitary beach in the mild evening air without our clothes, parts of our bodies continued luminous from the shining organic particles which had adhered to the skin, and the light only became extinct at the end of some minutes. Considering the enormous quantity of animal life in all tropical seas, it is, perhaps, not surprising that the sea water should be luminous, even where no visible organic particles can be detached from it. From the almost infinite subdivision of the masses of |