LUMINESCENCE AND INCANDESCENCE 



35 



bly serves as a reflector. Its significance will be dis- 

 cussed in a later chapter. 



The light of luminous organisms is quite generally 

 associated with granules. In one of the centipedes {Dry a 

 barbarica), which produces a luminous secretion, Dubois 



z 3 



%o 



O 

 « o O 



o 



O 



7 



Fig. 5. — Dubois's figures showing trans- 

 formation of photogenic granules to crystals 

 (after Dubois). 



(1893) has described the transformation of these granules 

 into crystals and at one time he supposed the light to be 

 a crystalloluminescence. He later reversed this opinion 

 and, certainly, examination of his drawings which are 

 reproduced in Fig. 5 does not convince one of the actuality 

 of crystal formation. 



The phenomenon of lyoluminescence, described by 



