270 DISEASES OF THE HOKSB. 



of recurrent ophthalmia. On the contrary, the offspring of diseased 

 parents removed to high, dry regions and furnished with wholesome, 

 nourishing rations will nearly all escape. Hence the dealers take 

 colts that are still sound or have had but one attack from the affected 

 low Pyrenees (France) to the unaffected Catalonia (Spain), with 

 confidence that they will escape, and from the Jura Valley to Dau- 

 phiny with the same result. 



Yet the hereditary taint is so strong and pernicious that intelligent 

 horsemen everywhere refuse to breed from either horse or mare that 

 has once suffered from recurrent ophthalmia, and the French Govern- 

 ment studs not only reject all unsound stallions, but refuse service to 

 any mare which has suffered with her eyes. It is this avoidance of 

 the hereditary predisposition more than anything else that has 

 reduced the formerly wide prevalence of this disease in the European 

 countries generally. A consideration for the future of our horses 

 would demand the disuse of all sires that are unlicensed, and the 

 refusal of a license to any sire which has suffered from this or any 

 other communicable constitutional disease. 



Other contributing causes deserve passing mention. Unwholesome 

 food and a faulty method of feeding undoubtedly predisposes to the 

 disease, and in the same district the carefully fed will escape in far 

 larger proportion than the badly fed. But it is so with every other 

 condition which undermines the general health. The presence of 

 worms in the intestines, overwork, and debilitating diseases and 

 causes of every kind weaken the vitality and lay the system more 

 open to attack. Thierry long ago showed that the improvement of 

 close, low, dark, damp stables, where the disease had previously pre- 

 vailed, practically banished this affection. Whatever contributes to 

 strength and vigor is protective; whatever contributes to weakness 

 and poor health is provocative of the disease in the predisposed 

 subject. 



Symptoms. — The symptoms vary according to the severity of the 

 attack. In some cases there is marked fever, and in some slighter 

 cases this may be almost altogether wanting, but there is always a 

 lack of vigor and energy, bespeaking general disorder. The local 

 symptoms are in the main those of internal ophthalmia, with, in many 

 cases, an increased hardness of the eyeball from effusion into its 

 cavity. The contracted pupil does not expand much in darkness, nor 

 even under the action of belladonna. Opacity advances from the 

 margin, over a part or whole of the cornea, but so long as it is trans- 

 parent there may be seen the turbid, aqueous humor with or without 

 flocculi, the dingy iris robbed of its clear black aspect, the slightly 

 clouded lens and a greenish yellow reflection from the depth of the 

 eye. From the fifth to the seventh day the flocculi precipitate in the 

 lower part of the chamber, exposing more clearly the iris and lens, 

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