164 PHOSPHORESCENCE IN 
name of subjective phosphorescence, were first ac- 
curately described by Purkinje. 
Ritter, 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 hght 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 ‘Hssay 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 
