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The causes of internal ophthalmia are largely those of the external form 

 only, actiug with greater intensity or on a more susceptible eye. Severe 

 blows, bruises, punctures, etc., of the eye, the penetration of foreign 

 bodies into the eye (thorns, splinters of iron, etc.), sudden transition 

 from a dark stall to bright sunshine, to the glare of snow or water, con- 

 stant glare from a sunny window, abuse of the overdraw check-rein, 

 vivid lightning flashes, draughts of cold, damp air 5 above all, when the 

 animal is perspiring, exposure in cold rain and snowstorms, swimming 

 cold rivers, also certain general diseases like rheumatism, arthritis, in- 

 fluenza, and disorders of the digestive organs, may become complicated 

 by this affection. From the close relation between the brain and eye — 

 alike in the blood vessels and nerves — disorders of the first lead to 

 affections of the second, and the same remark applies to the persistent 

 irritation to which the jaws are subjected in the course of dentition. So 

 potent is the last agency that we dread a recurrence of ophthalmia so 

 long as dentition is incomplete, and hope for immunity if the animal 

 completes its dentition without any permanent structural change in the 

 eye. 



The symptoms will vary according to the cause. If the attack is due 

 to direct physical injury the inflammation of the eyelids and superficial 

 structures may be quite as marked as that of the interior of the eye. 

 If, on the other hand, from general causes, or as a complication of some 

 distant disease, the affection may be largely confined to the deei)er 

 structures, and the swelling, redness, and tenderness of the superficial 

 structures will be less marked. When the external coats thus compar- 

 atively escape the extreme anterior edge of the white or sclerotic coat 

 where it overlaps the border of the transparent cornea is in a meas- 

 ure free from congestion, and, in the absence of the obscuring dark 

 pigment, forms a whitish ring around the cornea. This is partly due 

 to the fact that a series of arteries (ciliary) passing to the inflamed iris 

 penetrate the sclei-otic coat a short distance behind its anterior border, 

 and there is therefore a marked difference in color between the general 

 sclerotic occupied by these congested vessels and the anterior rim 

 from which they are absent. Unfortunately the pigment is often so 

 abundant in the anterior part of the sclerotic as to hide this symptom. 

 In internal ophthalmia the opacity of the cornea may be confined to 

 a zone around the outer margin of the cornea, and even this may be a 

 bluish haze rather than a deep fleecy white. In consequence it becomes 

 possible to see the interior of the chamber for the aqueous humor and 

 the condition of the iris and pupil. The aqueous humor is usually tur- 

 bid, and has numerous yellowish white flakes floating on its substance 

 or deposited in the lower part of the chamber, so as to cut off" the view 

 of the lower portion of the iris. The still visible portion of the iris has 

 lost its natural, clear dark luster, which is replaced by a brownish or 

 yellosvish sere-leaf color. This is more marked in proportion as the 

 iris is inflamed, and less so as the inflammation is confined to the cho- 



