PERIODIC OPHTHALMIA. 



339 



contract. If the eye remains weak, it may be stimulated by the 

 application of a few drops of: — 



Nitrate of silver .. 

 Or, sulphate of zinc 

 Or, alam 

 Water 



2 grains. 



3 „ 

 6 „ 

 1 oz. 



Periodic Ophthalmia, or Moon Blindness. 



CAUSES AND NATURE. — This somewhat rare disease appears 

 to be brought on by bad sanitary arrangements .; and by the in- 

 jurious influences of wet, marshy pastures on which horses are 



Opiic I 



SclerotUay,. r> 

 Choroid- 



Eyelid. 



Conjvinctwu/ 

 ■^-EyelasJv 



— fris 

 -ComecL 



-■■Aqueous hxunoar 



- Crystalline lens 



Ins 



'KytlasJu 

 Eyelid, 



Fig. 140.— Longitudinal and vertical section of eye. 



reared. In its production, hereditaiy predisposition plays a large 

 part. For instance, using; for stud purposes, stallions whose eyes 

 were affected, was formerly a frequent cause of blindness among 

 Irish horses. The frequency of its occurrence has diminished in 

 direct proportion to the improvement made in stable life, especially 

 as regards ventilation, and the consequent removal of the irritating 

 presence of ammonia. I have never seen a case of periodic oph- 

 thalmia in horses which had been always kept under healthy con- 

 ditions, and look upon it as a disease due to chemical or mechanical 

 irritation, and not as an infective malady. 



This disease appears to be an inflammation of the whole structure 



22* 



