DISEASES OF THE EYE. 295 



The attacks vary greatly in severity in different cases, but the 

 recurrence is characteristic, and all alike lead to cataract and intra- 

 ocular effusion, with pressure on the retina and abolition of sight. 



Prevention. — ^The prevention of this disease is the great object to 

 be aimed at, and this demands the most careful breeding, feieding, 

 housing, and general management, as indicated under " Causes." 

 Much can also be done by migration to a high, dry location, but for 

 this and malarious affections the improvement -of the land by drain- 

 age and good cultivation should be the final aim. 



Treatment is not satisfactory, but is largely the same as for com- 

 mon internal ophthalmia. Some cases, like rheumatism, are benefited 

 by 1-scruple doses of powdered colchicum and 2-dram doses of sali- 

 cylate of soda twice a day. In other cases, with marked hardness of 

 the globe of the eye from intraocular effusion, aseptic puncture of the 

 eye, or even the excision of a portion of the iris, has helped. During 

 recovery a course of tonics (2 drams oxid of iron, 10 grains nux 

 vomica, and 1 ounce sulphate of soda daily) is desirable to invigorate 

 the system and help to ward off another attack. The vulgar resort to 

 knocking out the wolf teeth and cutting out the haw can only be con- 

 demned. The temporary recovery would take place in one or two 

 weeks, though no such thing had been done, and the breaking of a 

 small tooth, leaving its fang in the jaw, only increases the irritation. 



CATARACT. 



The common result of internal ophthalmia, as of the recurrent 

 type, may be recognized as described under the first of these dis- 

 eases. Its offensive appearance may be obviated by extraction or 

 depression of the lens, but as the rays of light would no longer be 

 properly refracted, perfect vision would not be restored, and the 

 animal would be liable to prove an inveterate shyer. If perfect 

 blindness continued by reason of pressure on the nerve of sight, no 

 shying would result. 



PALSY OP THE NERVE OF SIGHT, OR AMAUROSIS. 



Cwmes. — The causes of this affection are tumors or other disease 

 of the brain implicating the roots of the optic nerve, injupy to the 

 nerve between the brain and eye, and inflammation of the optic nerve 

 within the eye (retina), or undue pressure on the same from drop- 

 sical or inflammatory effusion. It may also occur from overloaded 

 stomach, f I'om a profuse bleeding, and even from the pressure of the 

 gravid womb in gestation. 



Syrthftoma. — The symptoms are wide dilatation of the pupils, so 

 as to expose fully the interior of the globe, the expansion remaining 



