DISEASES OF THE BYE. 271 



and absorption commences, so that the eye may be cleared up in ten or 

 fifteen days. 



The characteristic of the disease is, however, its recurrence again 

 and again in the same eye until blindness results. The attacks may 

 follow each other at intervals of a month, more or less, but they show 

 no relation to any particular phase of the moon as might be inferred 

 from the familiar name, but are determined rather by the weather, 

 the health, the food, or by some periodicity of the system. From five 

 to seven attacks usually result in blindness, and then the second eye is 

 liable to be attacked until it also is ruined. 



In the intervals between the attacks some remaining symptoms 

 betray the condition, and these become more marked after each suc- 

 cessive access of disease. Even after the first attack there is a bluish 

 ring round the margin of the transparent cornea. The eye seems 

 smaller than the other, at first because it is retracted in its socket, and 

 often after several attacks because of actual shrinkage (atrophy). 

 The upper eyelid, in place of presenting a uniform, continuous arch, 

 has about one-third from its inner angle an abrupt bend, caused by 

 the contraction of the levator muscle. The front of the iris has 

 exchanged some of its dark, clear brilliancy for a lusterless yellow, 

 and the depth of the eye presents more or less of the greenish yellow 

 shade. The pupil remains a little contracted, except in advanced and 

 aggravated cases, when, with opaque lens, it is widely dilated. If one 

 eye only has suffered, as is common, the contrast in these respects with 

 the sound eye is all the more characteristic. Another feature is the 

 erect, attentive carriage of the ear, to compensate to some extent for 

 the waning vision. 



The attacks vary greatly in severity in different cases, but the recur- 

 rence is characteristic, and all alike lead to cataract and intraocular 

 effusion, with pressure on the retina and abolition of sight. 



Prevention. — The prevention of this disease is the great object to 

 be aimed at, and this demands the most careful breeding, feeding, 

 housing, and general management, as indicated under " Causes." Much 

 can also be done by migration to a high, dry location, but for this and 

 malarious affections the improvement of the land by drainage and 

 good cultivation should be the final aim. 



Treatment is not satisfactory, but is largely the same as for com- 

 mon internal ophthalmia. Some cases, like rheumatism, are benefited 

 by scruple doses of powdered colchicum and 2-dram doses of salicylate 

 of soda twice a day. In other cases, with marked hardness of the 

 globe of the eye from intraocular effusion, aseptic puncture of the 

 eye, or even the excision of a portion of the iris, has helped. During 

 recovery a course of tonics (2 drams oxide of iron, 10 grains nux 

 vomica, and 1 ounce sulphate of soda daily) is desirable to invigorate 

 the system and help to ward off another attack. The vulgar resort to 



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