103 MOON EYES. 



cornea), are, in inflammation, so increased in their 

 diameter, that they can admit the red parts of the 

 hlood to pass through them, which before only 

 allowed the almost colourless part to pass ; and the 

 minute vessels of the cornea, which carry lymph 

 (the watery or serous part of the blood) are also, 

 in inflammation, enlarged in their diameter : so 

 that this fluid, by being increased in quantity, 

 renders the cornea less transparent : — the former 

 explains why the eye appears red, and the latter, 

 how the surface of the eye becomes dim, whenever 

 inflammation attacks this important organ. When 

 the cornea becomes completely opaque, from the 

 severity of inflammation, this opacity is chiefly 

 owing to an effusion of coagulable lymph within 

 the vessels. This inflammation of the eye, though 

 it may be cured, is very apt to return again, and, 

 from its frequent attacks, it at last gives rise to 

 cataract, an affection of the eye which consists of 

 an opacity of the crystalline humour within the 

 globe, or of the delicate membrane with which that 

 humour is lined ; but I have always found both the 

 humour and its membrane affected in cataract. 

 This opacity diminishes, or totally extinguishes the 

 sight, by its interrupting the passage of light to 

 the retina : after cataract is formed, the disease, I 

 believe, never returns again in that eye. 



