DISEASES OF THE EYE. 131 



three images of it will be seen. First an erect image moving upwards 

 and downwards, according as the candle is moved. This image is pro- 

 duced by reflection of the surface of the cornea. Secondly, another erect 

 image produced from the anterior surface of the lens; this also moves 

 upwards and downwards, according as the candle is moved upwards and 

 downwards. Thirdly, a small inverted image reflected from the posterior 

 surface of the lens; this moves downwards when the candle is moved 

 upwards. 



In lenticular cataract, in the early stage, the inverted image is indis- 

 tinct. In its later stage it cannot be seen at all. When the cataract has 

 fully formed, the deep erect image is invisible. In capsular cataract only 

 the front image is visible. 



Treatment. — Veterinary science knows no cure for true cataract. 

 We cannot avail ourselves of those operations which in the human sub- 

 ject are so valuable, not indeed for the cure, but for the relief of this 

 disease. The horse possesses a very jieculiar power of withdrawing at 

 will his eye into its socket, which would much increase the difficulty of 

 performing any operation; but even if this diflBculty be got over, the oper- 

 ations common in human surgery would not be of any use, as it is obvi- 

 ously impossible to supply the horse with glasses. 



SPURIOUS CATARACTS. 



Spurious cataracts are opaque specks on the cornea, or flocculi of 

 lymph in the anterior chamber of the aqueous humor, generally adherent 

 to the anterior surface of the capsule of the lens or to the posterior sur- 

 face of the cornea. They are generally the result of common ophthalmia 

 and consist of an effusion of lymph into the aqueous humor. They oc- 

 casionally occur as a result of the specific disease. 



Spurious cataracts are frequently absorbed after a time. Sometimes 

 they appear quite suddenly and without any apparent cause, and disap- 

 pear as suddenly. 



AMAUROSIS. 



Synonyms. — Glass eye; Gutta serena. 



Amaurosis, partial or complete, results from paralysis of a part or of 



