164 PHOSPHORESCENCE IN 



name of subjective phosphorescence, were first ac- 

 curately described by Purkinje. 



Bitter, Purkinje, and Hjort have noticed that 

 when the eye is included in a galvanic current, a 

 vivid flash of light is perceived whenever this cir- 

 cuit is closed or opened. Purkinje also remarked 

 that whenever the eye is pressed with the finger 

 certain arborescent figures are produced, all of 

 which are luminous. 



Narcotic medicines often affect the eyes in a 

 similar manner, producing subjective phosphoric 

 radiations. A production of light in the above 

 circumstances is exceedingly interesting, and 

 tends, perhaps more than we are aware, to esta- 

 blish the fact that the phenomena of light are 

 owing to a vibratory 'movement of matter. 



In a former chapter I have spoken of the ap- 

 pearance of phosphorescent light upon the bodies 

 of animals, and upon the human body after death. 

 In this one I have to mention similar appearances 

 upon the living body. 



Marsh, in an c Essay upon the Evolution of 

 Light from the Human Subject/ brings forward 

 the following statement made to him in these 

 words : " About an hour and a half before my 

 sister's death, we were struck by luminous ap- 

 pearances proceeding from her head in a diagonal 

 direction. She was at the time in a half recum- 

 bent position and perfectly tranquil. The light 



