S6 ON THE EYE. 



surface of the chrystalline lens through which 

 the rays of light pass to the retina. 



The crystalline lens is a pellucid transparent 

 convex body, situated immediately behind the 

 pupil*. It frequently becomes opaque, in con- 

 sequence of general inflammation in the globe 

 of the eye. In this state the surface of the 

 lens, which presents itself in the cavity of the 

 pupil, assumes a greyish aspect, and in the con- 

 firmed state it becomes perfectly white. 



At the commencement of this disease, small 

 grey specks, about the size of a pin's head, are 

 sometimes perceived in the pupil, so small as 

 not to interrupt the entrance of light ; but the 

 presence of these specks is a certain indication 

 that the eyes have been attacked at some former 



* The crystalline lens is more or less convex in different 

 animals. In fish it is perfectly spherical, as the aqueous 

 medium which surrounds them, renders a greater refraction 

 of the rays necessary to vision. 



period 



