soil in which bacterial ferments are constantly producing them.

Heredity is one of the most potent causes. The lymphatic constitution 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 parent
has already suffered. Thus a mare may have borne a number of sound
foals, and then fallen a victim to the malady, and all foals
subsequently borne have likewise suffered. So it is in the case of 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 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 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 Government 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 feed 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; it is so also 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