THE NERVOUS SYSTEM 379 



INJURIES AND DISEASES OF THE EYE. 



633. The Eye, although well shielded by a strong bony socket, 

 cartilaginous, muscular, and membranous structures, is frequently 

 subject to injury and disease. 



634. The Eyelids are sometimes injured as a result of fighting, 

 more particularly in dogs. In the horse the upper lid is occasionally 

 torn by hooks, nails, etc. Should the piece hang down over the front 

 of the eye, the best plan is to cut it off, and treat the place as a simple 

 wound, or, if practicable, a suture or two may be put in and the 

 wound covered with collodion. Warty growths, when present, can 

 be removed with the scissors or the knife- The eyelids may become 

 inverted or everted. When the former happens, the eyelashes turn 

 inwards and irritate the front of the eye ; when the latter occurs, they 

 turn outwards. Both cases cause much pain and annoyance, and 

 have to be relieved by an operation, which consists of cutting a piece 

 out of the lid. The succeeding inflammation should be treated with 

 the following soothing eye lotion : boracic acid, 1 drachm ; wine of 

 opium, 2 drachms ; rose-water, -| pint ; apply with a soft sponge 

 night and morning. If great pain be present, a solution of cocaine 

 or extract of belladonna may be used. The animal should always 

 be kept in a dark place, and fed on a cooling diet. 



635. The Membrana Nictitans, or Haw, a cartilaginous 

 structure in the inner corner of the eye {Plate XXXIX., A 3), is 

 sometimes subject to irritation and inflammation, but is more prone 

 to warty growths and soft, spongy, and cancerous tumours. The 

 warts may be successfully cut off with the scissors, but in removing 

 the soft tumours the haw in some cases has to be excised altogether. 

 After the operation the parts should be dressed with the boracic 

 lotion already recommended. These, growths are more frequently 

 seen in the cow than in the horse. Old-fashioned farriers used to 

 cut the haw out for an imaginary complaint in pigs, called the 

 1 howks,' which was really indigestion ; they took up the haw with a 

 needle and thread and cut it out with the scissors. 



