AND HIS DISEASES. 171 



AMAUROSIS, OE GLASS EYE, 



Consists in either partial or complete paralysis of the optic 

 nerve, or its terminal expansion, the retina. 



(/(XMses.^-Injuries to the train, causing an extravasation of 

 blood upon the deep origin of the special nerve of sight, 

 (optic,) from disease of the internal coat of the eye (retina.) 

 It occasionally occurs as a sequel of stomach staggers or in- 

 digestion. We have also known it to occur in pregnant 

 mares. " Percival mentions several cases of amaurosis occur- 

 ring in mares in foal, where vision was perfectly restored after 

 parturition." 



Symptoms. — The eye has a peculiar glassy appearance ; the 

 horse carries his head very high, and is continually moving 

 his ears, and his action is high, lifting his feet as if he was 

 stepping over some obstacle. He is easily alarmed by any 

 noise. The pupil is dilated, and loses its natural elliptical 

 form. If the glare of a lighted candle is brought to bear 

 upon the eye, the pupil refuses to contract, thus showing 

 that nervous influence is lost. 



Treatment. — The horse should have rest, and a strong 

 dose of purgative medicine given. If supposed to arise from 

 efiusion or pressure on the nerve (optic,) blisters and setons 

 to the poll are recommended, and diuretics should be used. 

 In some instances the powdered nux vomica, in doses of one 

 scruple twice a-day, has been used with advantage. If 

 amaurosis has continued for a lengthened period, it is in- 

 curable, and treatment in such cases would be entirely use- 

 less. , 



CATARACT 



Is the name applied to a deposition of a pearly white 

 substance within the eye, and is a very common affection in 

 Canada. It consists in an effusion of lyniph either on the 



