222 Diseases of the Eyes and Ears. 
involved in the inflammation in common with other 
tissues of the organ. 
Symptoms.—The colour of the iris is changed to a 
reddish brown, by the presence of blood and the 
bringing into view blood-vessels not discernible in the 
healthy state, and the colour spreads also beyond the 
circle of the cornea. The patient cannot bear the light, 
and to shut it out the pupil contracts, and is more or 
less immovable by reason of the inflamed condition of 
the structures. The unopposed progress of the disease 
leads to extravasation of blood, deposit of opaque lymph, 
possibly the formation of pus, and total destruction of 
the organ as far as vision is concerned. 
Treatment.—Local bloodletting by lancet or leeches ; 
hot fomentations; secure free action of the bowels, the 
patient being kept ina dark, but airy room. Considerable 
fever is usually present, which must be met by febrifuges ; 
and when it has subsided daily doses of iodide of 
potassium with extract of gentian may be given to 
remove the deposit of inflammation. A seton behind 
the head is often beneficial. 
Amaurosis, or Gutta Serena, also known as Glass 
£ye, is a serious impairment of vision, due to disordered, 
if not structural, changes in the condition of the optic 
nerve, retina, or brain, the result of violent shocks, as 
falls, blows, &c. The first effect is probably paralysis, 
or inflammation accompanied with extravasation of blood, 
lymph deposits, or formation of tumour, with ultimate 
suspension or total loss of nerve power. The disease 
may be associated with extreme debility, the result of 
anemia, haemorrhage, inordinate lactation, or other 
causes, 
Symptoms.—Defective vision, in some instances de- 
veloping slowly, and in others very suddenly. In the 
first instance the animal fails to see objects until he is 
close upon them, and in the latter he approaches with 
great caution and uncertainty, usually relying on his 
acute sense of smell as he moves about alone. UIlti- 
mately the power of vision is entirely absent. Any signs 
of unusual heat, pain, or redness of the eyes, or cloudi- 
