251 



finger of the otlier hand, or over a probe laid flat against the middle of 

 the lid. Where the interior of the eye must be examined it is useless 

 to make the attempt in the open sunshine or under a clear sky. The 

 ■worst cases, it is true, can be seen under such circumstances, but for 

 the slighter forms the horse should be taken indoors, where all light 

 from above will be shut off, and should be placed so that the light shall 

 fall on the eye from the front and side. Then the observer, placing him- 

 self in front of the animal, will receive the reflected rays from the cor- 

 nea, the front of the lens and the back, and can much more easily detect 

 any cloudiness, opacity, or lack of transparency. The examination 

 can be made much more satisfactory by placing the horse in a dark 

 chamber and illuminating the eye by a lamp placed forward and out- 

 ward from the eye which is to be examined. Any cloudiness is thus 

 easily detected, and any doubt may be resolved by moving the lamp so 

 that the image of the flame may be passed in succession over the whole 

 surface of the transparent cornea and of the crystalline lens. Three 

 images of the flame will be seen, the larger one upright, reflected from 

 the anterior surface of the eye ; a smaller one upright, reflected from 

 the anterior surface of the lens ; and a second small one inverted from 

 the back surface of the lens. So long as these images are reflected 

 from healthy surfaces they will be clear and perfect in outline, but, as 

 soon as one strikes on an area of opacity, it will become diffused, cloudy, 

 and indefinite. Thus, if the large upright image becomes hazy and im- 

 perfect over a particular spot of the cornea, that will be found to be the 

 seat of disease and opacity. Should the large image remain clear, but 

 the small upright one become diffuse and indefinite over a given point, 

 it indicates opacity on the front of the capsule of the lens. If both 

 upright images remain clear, while the inverted one becomes indistinct 

 at a given point, then the opacity is in the substance of the lens itself 

 or in the posterior part of its capsule. 



If in a given case the pupil remains so closely contracted that the 

 deeper jiarts of the eye can not be seen the eyelids may be rubbed with 

 extract of belladonna, and in a short time the pupil will be found 

 widely dilated. 



DISEASES OF THE EYELIDS. 



Congenital disorders. — Some faulty conditions of the eyelids are con- 

 genital, as division of an eyelid in tico, after the manner of harelip, ab- 

 normally small opening between the lids, often connected with imperfect 

 development of the eye, and closure of the lids by adhesion. The first is 

 to be remedied by paring the edges of the division and then bringing 

 them together, as in torn lids. The last two, if remediable at all, re- 

 quire separation by the knife, and subsequent treatment with a cooling 

 astringent eye wash. 



Nervous disorders. — Spasm of the eyelids may be owing to constitutional 

 susceptibility, or to the presence of local irritants (insects, chemical 



