588 History of Luminescence 



luminescence work. Later histological and physiological studies 

 came in the next century. 



Pyrosoma and Salpa 



Pyrosoma, the fire cylinder or fire body, a colony of small tunicate 

 animals, was named by Francis Peron (1775-1810) , one of the natur- 

 alists on the Baudin expedition to Australia and New Zealand in 

 1800-1804. His memoir (1804) particularly stressed the brilliance 

 of the various luminescent colors exhibited, " le rouge, I'aurore, 

 I'orange, le verdatre, et le blue d'azur." Jean Bory de St. Vincent 

 (1780-1846), describing his finds on a trip to the four islands of 

 the African sea, called the fire cylinder Monophora noctiluca in 

 1804, and all explorers and observers (H. Kuhl, 1822; F. D. Bennett, 

 1833; F. J. F. Meyen, 1834) since that time have exclaimed at the 

 beauty of the light at night. Thomas Huxley (1825-1895) during 

 the voyage of the " Rattlesnake " in the Atlantic on June 15, 1850, 

 wrote, 



[The ship] drifted, hour after hour through this shoal of miniature 

 pillars of fire gleaming out of a dark sea, with an ever-waning ever- 

 brightening, soft bluish light, as far as the eye could reach on every 

 side. . . . The light commenced in one spot, apparently on the body of 

 one of the " zooid's," and gradually spread from this as a center in all 

 directions; then the whole was lighted up; it remained brilliant for a 

 few seconds, and then gradually faded and died away until the whole 

 mass was dark again. 



H. N. Moseley, speaking of the light of the sea in his book. Notes 

 of a Naturalist on the Challenger (1879) wrote: 



A giant Pyrosoma was caught by us in the deep-sea trawl. It was like 

 a great sac, with its walls of jelly about an inch in thickness. It was 

 four feet in length, and ten inches in diameter. When a Pyrosoma is 

 stimulated by having its surface touched, the phosphorescent light breaks 

 out at first at the spot stimulated, and then spreads over the surface of 

 the colony as the stimulus is transmitted to the surrounding animals. I 

 wrote my name with my finger on the surface of the giant Pyrosoma, as 

 it lay on deck in a tub at night, and my name came out in a few seconds 

 in letters of fire. 



It is possible that observation of luminous Salpae goes back to 

 Aelian (a. d. 3) , who mentioned a flickering light coming from a 

 sea growth, which A. Steuer ^° believed might be the luminescence 

 of Salpa africana maxima which he observed as great chains in the 



^° A. Steuer, Leitfaden der Planktonkunde (1911: 1). 



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