]KFLAM]\iATION OF TIIE EYES. 991 



Simple Ophthalmia, or Inflammation of the Eyes, 



Is a common disease among horses, and consists of inflammation 

 of the conjunctival membrane covering the eye. 



Causes. — ^It may be produced by many different causes, and 

 perhaps the most common is from the introduction of a foreign 

 substance into the eye, as a hay seed, or chaff pickle becoming 



Fig. 853. 



a, Optic nerve; 6, Sclerotic; c, Choroid; d, Retina; e, Cornea; /, Iris; g, 

 h, Ciliary circle ; i, Insertion on crystalline lens ; j, Crystalline lens ; k, Crystalline 

 capsule ; I, Vitreous body ; m, ii, Anterior and posterior chamber ; o, Membrane 

 of aqueous humor; p, p, Tarsi; q, q, Fibrous membrane of eyelids; r, Elevator 

 muscle of upper eyelid ; s, «, Orbicularis muscle of eyelids ; t, /, Skin of eyelids ; 

 M, Conjunctiva; v, Membrane covering cornea ; x, Posterior rectus muscle ; y, 

 Superior rectus muscle ; z, Inferior rectus muscle ; iv, Orbital membrane. 



lodged in the external covering (cornea), or by direct injury to 

 the eyes, as from the blow of a whip, or something of the kind. 

 When from a blow or direct cause of injury, but one eye will be 

 affected, while if from cold, etc., both eyes will be involved. It is 

 also caused by allowing horses to stand in foul stables, especially 

 in the summer months, whereby ammoniacal gases are generated, 



