THE 

 NATURE OF ANIMAL LIGHT 



CHAPTER I 



LIGHT-PEODUCING OBGANISMS 



The fact that animals can produce light must have 

 been recognizedfrgaJ^s. earliest times- in countries where 

 fireflies^ana'giowworms abound, but it is only since the 

 perfection of the microsc ope tha t the phosphorescence o£ 

 the"s®/EE[®^light of damp wood and of dead fish and fleshj 

 has been proved to'be' duVtoJmng organigms. [Artstbtle 

 ; ; " ^ 1 slfand flesh and both Aristotle 



^ . ^^ .. _ _d. Robert Boyle in 1667 made 



many experiments to show that the light from all three 

 sources, as well as that of the glowworm, is dependent 

 upon a plentiful supply of air and drew an interesting 

 comparison between the light of shining wood and that of 

 a glowing coal. Boyle had no means of finding out the 

 true cause of the light and early views of its nature were 

 indeed fantastic. Even as late as 1800 Hulme concludes 

 from his experiments on phosphorescent fish that the 

 light is a "constituent principle of marine fishes" and 

 the "first that escapes after the death of the fish." It 

 was only in 1830 that Michaelis suspected the light of 

 dead fish to be the result of some living thing and in 

 1854 Heller gave the name Sarcina noctiluca to the sus- 

 pected organism. In 1875 Pfliiger showed that nutrient 

 media could be inoculated with small amounts of luminous 

 fish and that 'these would increase in size, like bacterial 



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