132 VETEEINABY MEDICINE AND SURGERY. 



the whole of the optic nerve. According to the degree of the affection, 

 the blindness may be total or partial. The eye is generally in all other 

 respects perfect. 



Etiology. — Disease of the optic nerve may proceed from various cau- 

 ses — either peculiar to that one nerve, such as excess of glare or heat, or 

 from pressure on it, such as that induced by the formation of a tumor 

 by extravasation of blood, or any morbid effusion, or it may proceed from 

 some abnormal condition of the brain generally. It may also proceed 

 from some abnormal condition of the body, such as an overloaded 

 stomach, which affects the nervous system generally, and with it the 

 nerve of the eye. 



Amaurosis is also occasionally, though but rarely, the result of the vio- 

 lent inflammatory action of specific ophthalmia; and it occasionally arises 

 from extreme debility of the whole system from any cause, as from ex- 

 cessive loss of blood. Pressure from a fall backward or a blow on the 

 head may also bring on the disease. 



Treatment. — The treatment of amaurosis must depend on the cause 

 from which it is supposed to arise. When originating in atrophy or 

 shrinking of the optic nerve it is incurable. 



Tumors and morbid effusions on the brain are sometimes removed by 

 nature, and with their removal the optic nerve may recover its tone. Art 

 can do but little to assist in promoting this change. 



In oppression of the brain induced by an overloaded or disordered 

 condition of the stomach, a dose of laxative medicine will be useful: 



Linseed oil § x. to xij. 



To be given in a mash ; 



Or, 



Powdered aloes 3 ij. to vi. 



Linseed meal sufficient 



To make one ball with molasses. 



On the other hand, if the disease is connected with general debility, gen- 

 erous diet and tonics will be of service. 



In all cases, as topical remedies, cold applications to the head and 

 diminished light are to be recommended. 



