482 
DEPARTMENT OF SURGERY. 
patients, because animals do not protect themselves against 
secondary infection, which is favored in lower animals by their 
environment; but, even with such unfavorable conditions, there 
are instances when the operation is indicated and the results 
from the procedure are sometimes very good. 
Fig. 57. 
CIRCULATION OF THE EYE. 
a, sclera ; b, straight muscles; c, conjunctiva; d , cornea; <r, iris ; /, ciliary muscles ; g r 
canal of Schlemm ; 1, posterior ciliary arteries ; 2, anterior and posterior conjunctival arteries ; 
3, anterior ciliary arteries ; 4. Sclero-corneal plexus (capillary); 5, venae vorticosae. 
Indicatiojis .—Any vascular condition of the cornea that can¬ 
not be improved otherwise is an indication for the operation; 
but, we must not treat all vascular cornese by such intervention, 
for there are many of these cases that will yield to other treat¬ 
ment. Vascularization of the cornea may be a sequel of trach¬ 
oma, entropion, trachiasis, or, result from hypernutrition. When 
the vascularity occurs as a sequel of entropion or trachiasis, it 
is usually lessened by the removal of the cause; especially* 
