84 avery's own farrier. 



listen a few moments, to learn what my views are in re- 

 lation to this membrane, and disease of the eye. 



The fact is, that instead of this membrane, as it has 

 been called and described above — the hoise has a tube 

 or sack (which answers a similar purpose to the eye, as 

 the oil sack found on the rump of fowls does them, that 

 we often see them oil their feathers from), that is situated 

 in the corner of each eye, and from which oozes, by the 

 motion of the eye, a liquid or oil}' substance, which tends 

 to moisten the eye and render the sight more keen and 

 nice, as well as to assist in clearing the eye from dirt 

 accidentally entering it — and also another tube which 

 conveys the tear, as I shall call it here, to the nose, &c. ; 

 and whenever these tubes are closed, or an even flow of 

 the matter therein contained is checked, by inflammation 

 or fever, as they often are, the eye looks glassy, or has 

 the appearance of film. The primary causes, however, 

 are various, as being kept in dark stables, and then led 

 out to a full glare of light; filthy and ill-ventilated ones, 

 where the horse is obliged to stand enveloped in the 

 gases that arise from the excrements, &c.; with many 

 others that might be mentioned; and one of which is, 

 the horse from two to six years of age is subject to have 

 what are commonly called wolf teeth, which come in 

 front and close to the grinders, and in fact is one, of 

 those they shed, of the upper jaw; and is a small round 

 tooth which sometimes causes blindness by the pressure 

 on the nerve leading to the eye. The blindness caused 

 in this way come on more gradually, however, than 

 when caused by inflammation. So whenever the sight 

 becomes dim or imperfect (at this age), it will be well 



