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of health. The presence in the system of a definite germ has not yet 

 been proven, and in the present state of our knowledge we are only 

 warranted in eharging the disease on the deleterious emanations from 

 the marshy soil in which bacterial ferments are constantly producing 

 them. 



Heredity is one of the most potent causes. The lymphatic constitu- 

 tion is of course transmitted and with it the proclivity to recurring 

 ophthalmia. This is notorious in the case of boih parents, male and 

 female. The tendency appears to be stronger, however, if either parent 

 has already suffered. Thus a mare may have borne a number of sound 

 foals, and then fallen a victim to this malady, and all foals subsequently 

 borne have likewise suffered. So with the stallion. Reynal even 

 quotes the appearance of the disease in alternate generations, the 

 stallion offspring of blind parents remaining sound through life and yet 

 producing foals which furnish numerous victims of recurrent ophthal- 

 mia. 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 escai)e, 

 and from the Jura Valley to Dauphiny 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 

 formerl^^ wide prevalence of this disease in the European countries gen- 

 erally. 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 ouy other communicable con- 

 stitutional 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 prevailed, 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. 



The symptoms vary according to the severity of the attack. In some 

 cases there is marked fever, and in other slighter cases this may be 



