114 HEALTH AND DISEASE 



a caustic pencil should be drawn across the mucous membrane so as 

 to occasion a slough, when the lid will be drawn up or down in the 

 process of cicatrization. 



DISEASES OF THE LACHRYMAL APPARATUS 



Disease of the lachrymal gland, which secretes the tears, and obstruction 

 of the lachrymal duct, which carries any excess of their secretion into the 

 nasal cavity, are morbid conditions only occasionally met with in veterinary 

 practice in this country. The same remark may be made of redness and 

 ulceration of the edges of the lids with the loss of eyelashes, " Blepharitis 

 ciliaris"; constriction of the opening of the eyelids, " Blepharophimosis " ; 

 irregular arrangement of the eyelashes, " Triachiasis " ; adhesion of the 

 eyelid to the globe of the eye, " Symplepharon " ; and other affections 

 which are met with in the human subject but are seldom seen in the 

 eye of the horse. 



DISEASES OF THE CONJUNCTIVA AND CORNEA 



Simple Ophthalmia. Inflammation of the membrane which lines the 

 eyelid (conjunctiva) is known as simple ophthalmia or conjunctivitis. The 

 disease may present itself in various forms, from the acute to the chronic. 

 In all stages of the disease the normal secretion from the membrane under- 

 goes certain changes, and in the human subject the terms catarrhal, puru- 

 lent, and diphtheritic ophthalmia are employed to indicate the nature of 

 the discharge. 



Causes of simple ophthalmia are exposure to cold, the action of 

 irritating gases, dust, bits of chaff, and other foreign particles, injuries, 

 and it is very often associated with febrile diseases. 



A distinction may at once be drawn between inflammation of the 

 conjunctiva resulting from the causes referred to and swelling of the 

 lids arising out of injury. The symptoms in the former case are less 

 sudden in their appearance, generally beginning with slight redness of 

 the membrane and an increased secretion of tears. As the disease ad- 

 vances the discharge becomes thicker, and more or less opacity of the 

 cornea may follow; the animal instinctively avoids exposure to a strong 

 light, and the swelling of the eyelids becomes gradually more marked. The 

 treatment of these cases will depend upon the stage which the disease has 

 reached. If the inflammation is of the sub-acute or chronic form astrin- 

 gent lotions may be applied at once, and a weak solution of sulphate of 

 zinc, two grains to the ounce of water, will be effective. It may be 



