408 LECTURE XXV. 



luminosity, when prevented from emitting the light, exhaled only as much carbon 

 dioxide as the substance which is not luminous at all. 



Fabre concludes his work with the reniark that phosphorescence is the effect of 

 the respiratory activity of the Fungus, and depends upon the same causes as the 

 spontaneous evolution of heat at the time of flowering in certain parts of Phanero- 

 gams, particularly the Aroidese. Nevertheless, it must be allowed that very peculiar 

 arrangements must exist for light to be a consequence of respiration in the Fungi, 

 since the flowers of the Aroidese, and even those of Cucurbita, form relatively far 

 larger .quantities of carbon dioxide, and develope heat without being luminous. The 

 taking up of oxygen is evidently only one of the various causes the co-operation of 

 which produce luminosity. 



