422 IOWA DEPARTMENT OF AGRICULTURE 
vision would not be restored, and the animal would be liable to prove an 
inveterate shyer. If perfect blindness continued by reason of pressure on 
the nerve of sight, no shying would result. 
PALSY OF THE NERVE OF SIGHT, OR AMAUROSIS. 
Causes. — The causes of this affection are tumors or other diseases of 
the brain implicating the roots of the optic nerve, injury to the nerve 
between the brain and eye, and inflammation of the optic nerve within 
the eye (retina), or undue pressure on the same from dropsical or in- 
flammatory effusion. It may also occur from overloaded stomach, from 
a profuse bleeding, and even from the pressure of the gravid womb in 
gestation. 
Symptoms. — The symptoms are wide dilation of the pupils, so as to 
expose fully the enterior of the globe, the expansion remaining the same 
in light and darkness. Ordinary eyes when brought to the light have 
the pupils suddenly contract, and then dilate and contract alternately 
until they adapt themselves to the amount of light. The horse does 
not swerve when a feint to strike is made unless the hand causes a cur- 
rent of air. The ears are held erect and turn quickly toward any noise, 
and the horse steps high to avoid stumbling over objects which it can 
not see. 
Treatment is only useful when the disease is symptomatic of some 
removable cause, like congested brain, loaded stomach, or gravid womb. 
When recovery does not follow the termination of these conditions, apply 
a blister behind the ear and give one-half dram doses of nux vomica 
daily. 
TUMORS OF THE EYEBALL. 
A variety of tumors attack the eyeball — dermoid, papillar, fatty, cystic, 
and melanotic — but perhaps the most frequent in the horF3 is encephaloid 
cancer. This may grow in or on the globe, the haw, the eyelid, or the 
bones of the orbit, and is only to be remedied, if at all, by early and 
thorough excision. It may be distinguished from the less dangerous 
tumors by its softness, friability, and great vascularity, bleeding on the 
slightest touch, as w^ell as by its anatomical structure. 
STAPHYLOMA. 
This consists in a bulging forward of the cornea at a given point 
by the saccular yielding and distention of its coats, and it may be either 
transparent or opaque and vascular. In the last form the iris has 
become adherent to the back of the cornea, and the whole structure has 
become filled with blood vessels. In the first form the bulging cornea 
is attenuated; in the last it may be thickened. Tlie best treatment is 
by excision of a portion of tlie rise so as to relieve the intraocular pres- 
sure. 
