488 



THE WONDER OF LIFE 



doubt that the production of light is one of the results of 

 this metabohsm. Just as heat is produced by the vital 

 activity of the muscles (their characteristic ' thermogenic ' 

 function) and by all the combustions that go on in the 

 body, so hght is produced in connexion with other chemical 

 processes involved in hving. Many facts point to the con- 



chr 



Fio. 78. — Phosphorescent cell. (After Watase.) c, Cytoplasm of the 

 cell ; OHB, Chromosomes of the nucleus — living constituents. 

 A, Food ; PH, Photogenic Granules — not living constituents. 

 Oxygen acts on the photogenic granules, and Light emanates 

 from the cell as the result of oxidation. 



elusion that the luminescence need not be in itseH of any 

 biological importance, any more than the heat produced 

 in the active brain is normally of any importance, any 

 more than the beautiful colour of some organic waste 

 products is in itself of any importance. But just as the 

 production of heat or of pigment may be turned to good 



