198 DISEASES OF THE HORSE. 



superficial tissues, or the cellular and fatty matters 

 surrounding the eyeball. The symptoms are marked 

 by great impatience of light and great pain on moving 

 the lids. 



If the extraneous matter be merely dust or sand, it 

 may be washed away by means of a syringe ; but if it 

 be of a sharp nature, such as glass, flint, or metal, it 

 must be instantly removed. If the lids be fully opened 

 in a good light the existence of foreign matter can be 

 readily seen and removed. A lead pencil or the corner 

 of a silk handkerchief should be used for removing the 

 foreign matter. This should be done without delay, in 

 order to avert the inflammatory action and ulceration, 

 always consequent on injuries to the cornea. 



In all wounds of the conjunctiva and surface of the 

 eye, where no extraneous matter has become retained, 

 lowering treatment, abstraction of blood from the facial 

 vein, with continual application of cold spring water to 

 ward off vascular excitement, are to be recommended. 

 Wounds, however, of the centre of the cornea of con- 

 siderable size, involving the internal structure of the 

 organ, are necessarily fatal to the vision. 



POLL EVIL. 



Poll evil consists in an abscess on or behind the 

 prominent ridge between the ears, and is caused by 

 knocking the head violently against a low beam, or 

 by lifting the head suddenly when eating up grains that 



