532 History of Luminescence 



mens of luminous animals. The opinion of Peron has been men- 

 tioned previously. Additional important statements are due to A. 

 von Humboldt, J. Macartney, and W. G. Tilesius von Tilenau. 



Alexander von Humboldt's ideas on the phosphorescence of the 

 sea came from his early expedition to South America in 1799-1802. 

 In later editions of the Views of Nature (1849) , which recorded 

 the mature reflection on his observations, he discarded the idea that 

 sea light was electrical, owing to friction along the sides of a vessel, 

 and declared it to come from living organisms. However, von Hum- 

 boldt's views were somewhat confused, as can be seen from the fol- 

 lowing quotations,-^ which attempt to explain how light can be 

 emitted by living things in general: 



The luminous animals of the ocean appear, from these conjectures, to 

 prove the existence of a magneto-electric light-generating vital process in 

 other classes of animals besides fishes, insects, mollusca, and acalephae. 

 Is the secretion of the luminous fluid which is effused in some ani- 

 malcules, and which continues to shine for a long period without further 

 influence of the living organism . . . merely the consequence of the first 

 electric discharge, or is it simply dependent on chemical composition? 

 The luminosity of insects surrounded by air assuredly depends on physio- 

 logical causes different from those which give rise to a luminous condi- 

 tion in aquatic animals, fishes. Medusae, and Infusoria. The small Infu- 

 soria of the ocean, being surrounded by strata of salt-water which con- 

 stitutes a powerful conducting medium, must be capable of an enormous 

 electric tension of their flashing organs to enable them to shine so vividly 

 in the water. They strike like the Torpedo, the Gymnotus, and the 

 Electric Silurus of the Nile, through the stratum of water: . . . 



Sometimes one cannot, even with high magnifying powers, discover 

 any animalcules in the luminous water: and yet, wherever water is vio- 

 lently agitated, flashes of light become visible. The cause of this phe- 

 nomenon depends probably on the decomposing fibers of dead Mollusca, 

 which are diffused in the greatest abundance throughout the water. . . . 



James Macartney (1810) had the advantage of Sir Joseph Banks' 

 observations on Captain Cook's expedition in 1768-1771. His con- 

 tribution to the Phil. Trans, in 1810 was entitled, " Observations 

 on Luminous Animals." After stimming up the various theories 

 previously mentioned and rejecting them all, he wrote: 



I shall not trespass on the time of the Society to refute the above specu- 

 lations; their authors have left them unsupported by either arguments 

 or experiments, and they are inconsistent with all ascertained facts upon 

 the subject. The remarkable property of emitting light during life is 



"A. von Humboldt, Views of nature, trans, by E. C. Ottd and H. G. Bohn, 248-249, 

 London, George Bell & Sons, 1875. 



