348 DISEASES OF CATTLE. 



puncturing the projecting tumor, and treating it afterwards with nitrate 

 of silver in the same manner as prescribed for ulceration of the cor- 

 nea. In some cases spontaneous rupture has occurred, and healing 

 without any treatment at all. 



CATARACT. 



In cataract the crystalline lens becomes opaque and loses its trans- 

 parency, the power of refraction is lost — the animal can not see. 



Causes. — Cataract generally arises from a diminution (atrophy) or 

 other change in the nutrition of the lens; it may occur as a result of 

 inflammation of the deep structures of the eye. Cataract may be sim- 

 ple, or complicated with amaurosis, adhesions, etc. 



Symptoms. — It is known by the whiteness or loss of transparency 

 of the lens, although the pupil dilates and contracts. Sight may be 

 totally lost; however, evidence is usually manifested that the animal 

 distinguishes light when brought out of a darkened stable. For the 

 most part the formation of cataract takes place slowly, the cases in 

 which it originates very quickly being but few. 



Treatment. — There is only one method for the treatment of cata- 

 rael — a surgical operation for the removal of the lens; but this is not 

 advisable, for the sight can not be perfectly restored, and objects 

 would be seen imperfectly without the aid of glasses. 



AMAUROSIS. 



A paralysis of the nerve of sight or the expansion of the retina. 



Causes.— This is the result of concussion from a blow upon the fore- 

 head, fracture of bone over the eye (causing downward pressure) , rheu- 

 matic inflammation of the optic nerve, or from extension of deep 

 inflammation of the eye involving the retina. It sometimes occurs as 

 the result of excessive loss of blood or of great debility. 



Symptoms. — In this disease seldom any observation is made until 

 the animal in its gait and by its action indicates blindness. Gener- 

 ally both eyes are affected. The eyeball remains clear, and the pupil 

 permanently dilated. No response to light is manifested. 



Treatment.— If due to debility, loss of blood, or associated with 

 rheumatism, general blood tonics may be given in the feed, namely, 

 powdered sulphate of iron, 1 dram*; gentian, 2 drams; nux vomica, 

 one-half dram; to be given twice a day. In cases of rheumatism, 

 one- half ounce of saltpeter may be added. 



FILARIA OCULI (WORM IN THE EYE). 



Filaria oculi (provisionally taken as the larva of F. cervina).— This 

 is a small white worm, and is found in the eye, swimming in the 

 aqueous fluid in the anterior chamber. Itmay be apparently harm- 

 less for a long time, but will eventually induce keratitis with inflam- 

 matory exudations. 



Treatment— The cornea may be punctured at its upper and outer 



