SOME REMARKS ON PERIODIC OPHTHALMIA. 
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flowed river bottoms, or marshy grounds, and on coasts of lakes 
and seas, alternately wet or dry, you will find this disease. In 
France, Germany, and Kngland, where they appreciate horses 
(and veterinarians) this disease has largely decreased under 
drainage, etc. Theie are many other influences,—for instance, 
cloud} air,- wet, damp climate and lands, as all these act to pro¬ 
duce lymphatic constitutions, with an excess of connective tis- 
sue ? bones and muscles, of coarse, open texture, thick skin, 
gummy ” legs, long, coarse hair, etc. For instance, the 
' heavy horses of Belgium and southwest France have suffered 
severely, while the high dry lands of Catalonia, Spain, and Dau- 
phinv, Provence, and Fanguedoc, in France, have been lightly 
touched. Rank, watery foods are another cause, and the most 
likely situations to obtain such fodder are as described above_ 
the marshy, wet lands. This rank feed undermines the nervous 
and sanguineous temperament and superinduces the lymphatic. 
Other foods act by leading to constipation. The period of den¬ 
tition and training is an exciting cause, and it will be noticed 
that moon-blindness ” appears most frequently between the 
ages of tv o and six. Among other causes are local irritants, 
dust, smoke, severe rain and snow, acrid vapors, etc. No one 
of the above mentioned causes will suffice to cause it. The al¬ 
leged cause is a microbe, or the irritant products of a microbe, 
which is harbored in the marshy soil. The prevalence of the 
disease on the same damp soils that produce ague in man and 
anthrax in cattle has been quoted in support of this. Also on 
certain farms irrigated by town sewage, we find plenty of cases 
of periodic ophthalmia. The presence of a definite germ in the 
system has not as yet been proven, and therefore, in the present 
u knowledge, we are only warranted in saying that 
the cause is in the deleterious emanations from the marshy soil 
m 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 recurrent ophthalmia. This is notorious in the case of both 
parents, male and female. The tendency appears to be strong, 
