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CHAPTER I. 

 EMISSION OF LIGHT BY DEAD ANIMAL MATTER, 



IN this section of my work I shall speak of the 

 emission of light by dead animal .matter, before 

 entering upon the subject of phosphoric animals. 



It is well known that when the dead bodies of 

 certain fish, more especially mackerels and her- 

 rings, are exposed to the air for a short time, 

 they soon become luminous in the dark. When 

 they are in this state, if we merely rub the finger 

 over the luminous surface of the dead fish, we re- 

 cognize the presence of an oily substance, which 

 renders the finger luminous, as if it had been 

 rubbed upon phosphorus. 



This grease, when separated from the body of 

 the fish by means of a knife, and placed upon a 

 plate of glass, continues to shine in the dark. 

 When examined under the microscope, not a ves- 

 tage of infusoria or other animalcule is seen in it, 

 which otherwise, as we shall see further, might 

 account for its luminosity. 



