DISEASES OF DOMESTIC ANI31ALS. 65 



irritation ; bathe with tepid water and laudanum. You may give ex- 

 tract of belladonna in drachm doses, and rub along the eyelids, or 

 you may use the active principle in the eye, but it is not necessary 

 unless the iris is affected to a considerable extent. There is benefit in 

 nitrate of potash and iodide of potash. Iodide of potash and colchicum 

 ons drachm each once or twice a day. If the acute symptoms have 

 passed off, the clearness may be hastened some by iodide of potassium 

 and nitrate of silver. Treatment does not do much but palliate the 

 disease. Apply something to allay the irritation of the eye— warm 

 water, or in some cases cold Water. If tbe iris is much affected, I think 

 belladonna is the best thing that can be used. Blisters have been used 

 to a great extent, but are not of much benefit. A little counter-irritation 

 may be of use ; first subdue the inflammatory action the best you can, 

 and expedite the removal of the products of inflammation. In most 

 cases it terminates in cataract. 



Cataract means a breaking up. Cataract may be capsular or lecticu- 

 lar ; the lens may be entirely destroyed, or only a slight deposition 

 which impairs vision to a slight extent. May have cataract, opacity of 

 the lens, or capsule, and so prevent the passage of light. Cataract is the 

 result of periodic ophthalmia, but it may re'sult from some other cau?e, 

 or without any observable cause, and may be due fo some nervous in- 

 fluence. You may have cataract without any noticeable irritation at all. 

 If capsule only is affected, it is called capsular. If the lens, it is 

 lenticular. It is a pearly white deposit. 



Result of Opthalmia is cataract. It is a term applied to what we call 

 opacity of the crystalline lens. Either the lens itself or the capsule in- 

 vesting the lens, and thus it gets different names, as capsular, lenticular, 

 and capsular-lenticular. It is the result of ophthalmia, but it may 

 occur independent of this, from injury, or without any irritation of any 

 consequence whatever. But this is not a common occurrence. It is 

 generally due to repeated attacks of ophthalmia. There is true and 

 false and spurious cataract. The true is opacity of the crystalline lens, 

 its capsule, or both lens and capsule. There is an opaque deposit of 

 lymph pus or blood on the anterior capsule It m^y involve the entire 

 lens, or only a part of it. There is a pearly white deposit in the anterior 

 part of the eye. Cataract is said to have been absorbed, but it was T 

 think, not true cataract, but false— animal having suffered from injury 

 or something which give rise to effusion, but it was a spurious form. 

 Cataract is occasionally congenital, i.e., at or soon after birth. If born 

 blind, it is generally in both eyes. Complete cataract is incurable. 



Symptoms. — If it is of any tize and involves the crystalline lens, it is 

 easily detected. According to its size and position, there is either j^artial 

 or complete blindness. Cataract may be present to some extent and 

 not produce complete blindness. If small, it is not so easily detected — 

 it may le overlooked. If it is small, the pupillary opening is contracted 

 if exposed to the rays of light. If it is completely formed, the iris loses 

 its natural condition, and does not contract. The pupil and the retina 

 may at the same time lose its natural condition, and you have amaurosis 

 and cataract. It requires some experience to detect it If you are 

 examining a horse, take him suddenly from the dark to the light, and 

 watch closely If the pupil contracts quickly, there is suspicion of some 

 irritation. Take a black hat and shade the eye, and notice the pupillary 

 opening, and you may be able to detect it. I3ut if you still have doubt, 

 place the animal in a dark box, and let him stand fifteen minutes, and 

 then take an artificial light and bring in front of the eye, and watch, and 

 you will sometimes be able to detect this white pearly deposit, but be sure 



