566 PHYSIOLOGY OF THE EYE OF THE HORSE. 
the same contaminated atmosphere which is known to engender 
glanders and farcy, sows the seeds of disease in the present 
instance. Horses running wild, and breathing the untainted 
open air, are seldom thus affected. 
It is, as you all know, a constitutional malady ; but how do 
we prove this? Why, first, by constitutional derangement, which 
can be traced to the digestive organs and the skin : secondly, the 
character of the inflammation, which is neither so acute, nor so 
rapidly progressive as simple ophthalmia often is, and yet the 
one readily yields to proper treatment, while the other obstinately 
continues its course: thirdly, its flying from one eye to the 
other proves to demonstration that it must be lurking in the 
constitution. 
The most rational indication of cure, or the treatment of a 
disease, is that founded on the removal of its cause. It is a 
common practice to draw blood, and now and then we appear 
to do so beneficially. The evacuation should not be sparing, 
and the jugular vein, on the same side as the affected eye, will be 
opened with the concurrent advantages of local and constitu¬ 
tional depletion. The temporal artery is sometimes chosen, but, 
in my opinion, without the prospect of equivalent benefit, since 
none of its branches run to the eyeball. The angular vein is 
opened with still less benefit. 
Various tonic and other medicines have been administered at 
random in the hope of drawing a prize, but they have, one and 
all, turned out blanks. The cupri sulphas has been started as 
a specific, but it has proved to be only a nine days’ wonder. 
The advocates for the locality of this affection, they who build 
their hopes upon various eye-powders, collyriums. See. have been 
equally foiled in their anticipations. 
I do not deny the occasional utility of some of these things, 
as co-operatives with constitutional measures ,* but of themselves 
they are valueless. 
Poppy and camomile fomentations are recommended, but they 
are teasing in their application : the horse, being a refractory 
sort of animal when he has a sore eye, has no notion of holding 
his head still to have it played with; but he may permit his eye¬ 
lids to be wetted occasionally with cold water, or the solution of 
subacetate of lead, which will answer all the purpose that may 
be required. 
Light and air being stimulants to the organ in health, it most 
undoubtedly ought to be shielded from both in disease. The 
animal, therefore, should be placed in a dark but well ventilated 
stable, and winkers ought always to be worn. 
By the judicious employment of these means, we commonly 
