Abstract
LUMINOUS bacteria constitute a group of organisms which under certain conditions have the power of emitting light. They occur principally, if not entirely, in sea-water. It is, however, doubtful whether they give rise to any general luminosity of the sea, such as is caused by noctiluca and other relatively high forms of marine life, although it is possible that in the tropics, where the amount of non-living nutritive material is present in sufficient quantities, that bacteria do occasionally cause a general luminosity; but the opportunities of verifying this are rare. One organism in particular, the Photobacterium Indicum, from its forming a surface pellicle in artificial fluid, cultures, which is very luminous, may at times cause luminosity of sea-water at the surface. It is remarkable that an unicellular organism such as a bacterium should have the,power of emitting light. There is no evidence of any special structure in the cell itself, and in the “present state of our knowledge it is difficult to regard it as other than a result of functional activity, exactly a heat is evolved by other forms of life, as an accompaniment of the metabolism of the cell. What is, however, the exact difference between the evolution of heat by some organisms and that of light by others it is at present impossible to say. Oxygen is absorbed in both instances and carbon dioxide evolved, but there is evidently some other factor of which at present we know nothing. The fact that light and heat are manifestations of the same form of energy may apparently simplify the matter; but further consideration shows that there is a different problem to be solved in each.
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BARNARD, J. Luminous Bacteria . Nature 65, 536–538 (1902). https://doi.org/10.1038/065536d0
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DOI: https://doi.org/10.1038/065536d0