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quoted in support of this doctrine, as also the fact that the malady is 

 always more prevalent center is paribus in basins surrounded b.y hills 

 where the air is still and such products are concentrated, and that a 

 forest or simple belt of trees will, as in ague, at times limit the area 

 of its i3revalence. Another argument for the same view is found in 

 the fact that on certain farms irrigated by town sewage this malady 

 has become extremely prevalent, the sewage being assumed to form a 

 suitable nidus for the growth of the germ. But on these sewage 

 farms a fresh crop may be cut every fortnight, and the product is 

 precisely that aqueous material which contributes to a lymphatic 

 structure and a low tone 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 charging the disease on the dele- 

 terious 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 both parents, male and 

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

 ent has already suifered. Thus a mare may have borne a number of 

 sound foals, and then fallen a victim to this malady, and all foals sul> 

 sequently borne have likewise suffered. So with the stallion. Rey- 

 nal 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 oj)h- 

 tlialmia. On the contrary, the offsijring 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 (Sixain), with confidence that they will 

 escape, 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 oi^hthalmia, and the French Govern- 

 ment studs not only rejept 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 Euroi3ean 

 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' j)redisposes 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 



