LUMINESCENCE AND INCANDESCENCE 39 



ski (1880) found the light of lophin oxidized in alcoholic 

 caustic alkali, examined with a two-prism spectroscope, 

 to give a continuous spectrum, brightest at E, with the 

 red and violet ends lacking. Trautz (1905, p. 101) states 

 that the pyrogallol-formaldehyde-Na^COa-HsOs reaction 

 gives a continuous spectrum from the red to the blue green 

 with maximum brightness in the orange. Weiser (1918 

 a) has studied the spectra of some chemiluminescent reac- 

 tions by photographing the light behind a series of color 

 screens. He finds also that the spectra are short, with 

 maximum intensity in various regions. Thus, amarin 

 oxidized by chlorine or bromine, extends from the yellow 

 to greenish blue with a maximum in the green while phos- 

 phorus, dissolved in glacial acetic acid and oxidized with 

 H2O2, luminesces from yellow green to violet. 



The spectra of luminous animals are quite similar to 

 those of chemiluminescent reactions. Moreover, as we 

 have seen, chemiluminescence is essentially an oxylumi- 

 nescence, since oxygen is necessary for the reaction. All 

 luminous animals also require oxygen for light production. 

 Therefore, bioluminescence and chemiluminescence are 

 similar phenomena and they differ from all the other 

 forms of luminescence which we have considered. The 

 light from luminous animals is due to the oxidation of 

 some substance produced in their cells, and when we can 

 write the structural formula of this photogenic substance 

 and tell how the oxidation proceeds, the problem of light 

 production in animals will be solved. 



