The Nineteenth Century 233 



except the first has had considerable to say on luminescence, al- 

 though the articles were scattered under such subjects as light, elec- 

 tricity, chemistry, phosphorus, etc. This treatment was continued 

 until the seventh edition (1830-1842) when the article on " Light," 

 written by T, S. T., contained sections on " Evolution of Light 

 without Appreciable Heat " and " Light Emanating from Living 

 Animals." 



In the ninth and tenth editions (1875-1889) there is a special 

 article on " Phosphorescence " by \V. E. Hoyle of the Challenger 

 Expedition Office, which treats of both inorganic luminescences and 

 bioluminescence. The latter word does not occur in the article, nor 

 can the words " luminescence " and " fluorescence " be found in the 

 index. Separate articles on these subjects only appeared in the later 

 editions of the twentieth century. 



evolution and bioluminescence 



The gieat revolution in biological thought which followed Charles 

 Darwin's (1809-1882) publication of The Origin of Species by 

 Means of Natural Selection (1859) had certain repercussions among 

 students of bioluminescence. It emphasized the use or value of an 

 organ to the animal, and turned attention to the purpose of light 

 emission. Post-Darwinian writers have regarded the light of ani- 

 mals as of use to attract the sexes or for species recognition marks, 

 to lure food where it could be easily caught, warn or confuse pre- 

 dators, and for actual illumination of the surroundings. 



Some of these categories are by no means recent. Thomas Bar- 

 tholin (1647) related the suggestion of Carolus Vintimillia that 

 " nature had endowed them [the female fireflies] with a more vigor- 

 ous light in order that they could call the males at night with their 

 shine," and M. de Flaugergues (1780) thought the light of earth- 

 worms might be involved in sex attraction. Later, nineteenth-cen- 

 tury pre-Darwinian writers also realized that some use must be 

 found for light production. J. MacCulloch (1821) said there could 

 be no light in the depths of the ocean and held that the luminous- 

 ness of organisms living there might be a means of seeing each 

 other. This view was upheld by Coldstream (1847) and others, but 

 objected to by Mcintosh (1872) . Carpenter, Jeffries, and Thomson 

 (1869: 432) also, in their preliminary report on the " Porcupine " 

 exploration of the depths, remarked on the large number of lumi- 

 nous species obtained, and held that it is " scarcely possible that the 

 sun's light can penetrate beyond 200 fathoms at most. ... It seems 

 to us probable that the abyssal regions might depend for their light 

 solely upon the phosphorescence of their inhabitants." This sup- 



