BIOLOGY OF LIGHT PRODUCTION — MALUF 387 



gen is replaced by irrespirable gases luminescence in Lampyris is abol- 

 ished. "The phosphorescence," wrote Carpenter (1854) concerning 

 luminescence in fireflies, "appears to be occasioned by the slow com- 

 bustion of a peculiar organic compound, the production of which is de- 

 pendent for its continuance upon the life and health of the animal ; the 

 activity of this combustion is stimulated by anything which excites the 

 vital functions of the individual, and it is particularly influenced by the 

 energy of the respiratory process. If the opening of the trachea which 

 supplies the luminous sac be closed, so as to check the access of air to its 

 contents, the light ceases [italics mine] ; but if the sac be Uf ted from its 

 place, without injuring the tracheae, the light is not interrupted. In 

 all active movements of the body in which respiration is energetic, the 

 light is proportionally increased in brilliancy. If the luminous seg- 

 ments be separated from the rest of the body, they continue phos- 

 phorescent for some time." The italicized observation shows that 

 there is no effective ventilation of the air in the tracheae of the lumi- 

 nescent organ by other spiracles than those belonging to the light- 

 producing segments (see also Heinemann, 1886; Hess, 1921; and 

 Maluf, 1938). In fact, Lyonnet's early observations (confirmed by 

 others, cf. Babak, 1921) show that ventilation is to a great extent seg- 

 mentally localized even in tracheates with as well developed a tracheal 

 system as caterpillars. Ofsianikof (1863) also found that the luminos- 

 ity of Lampyris noctiluca ceases in vacuo but recommences on the read- 

 mission of a little air and becomes very dull in an atmosphere con- 

 taining an excessive amount of carbon dioxid. Temporary immersion 

 in glycerin also caused a cessation of luminescence possibly due to a 

 plugging of the spiracles. The condition was quite reversible, how- 

 ever, upon washing with water, in which glycerin is soluble. That 

 oxygen is actually used up in the photogenic process itself and that the 

 absence of luminescence in the absence of oxygen is not merely due to a 

 general interference with the cellular functions was first shown by 

 Dubois who found that luminous extracts of arthropods and the mol- 

 lusk, Pholas, will not emit light in the absence of oxygen but will do so 

 upon the readmission of oxygen. These findings have been confirmed 

 by Kastle and McDermott (1910), Harvey (1916a, 1917b, 1920), and 

 others. 



Contrary results were presented by Kanda (1920, 1920a), who noted 

 that the intensity of light produced by an aqueous suspension of luci- 

 ferin-luciferase from the Japanese ostracod, Cypridina hilgendorfii 

 is strongest and lasts longest in water saturated with hydrogen 

 from which other gases, including oxygen, had been discharged. The 

 intensity of light produced by a luciferin-luciferase suspension of this 

 animal was weakest and lasted least in water saturated with oxygen. 

 Although Kanda admitted that very little oxygen might have been 

 present in spite of elaborate precautions, he concluded that the produc- 



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