122 VETERINARY OPHTHALMOLOGY. 



lens, is a readily transfusible membrane. The pres- 

 sure in the aqueous and vitreous are equal, and this 

 equilibrium must be maintained to have a normal eye. 

 Tiie slightest excess will destroy its function in cor- 

 responding degree. This equilibrium is rendered 

 stable by due secretion and excretion of the fluids. 

 The intra-ocular fluids flow from the blood stream. 

 The ciliary body supplies the fluid to the vitreous, 

 aqueous and lens. Most of the secretion passes 

 directly to the aqueous by means of the pupil and filtra- 

 tion angle. A very much smaller portion passes back- 

 ward and out through the papilla. The most impor- 

 tant change v/hich takes place in glaucoma will be 

 found at the iritic angle, affecting the vessels compos- 

 ing or entering into Schlemm's canal. These are 

 inflammatory, and the iris becomes adherent to the 

 cornea and closes up Fontana spaces partially or wholly, 

 thus hindering the excretion of the fluids, and so aug- 

 ments the condition. The fibers of the optic nerve 

 become inflamed, and atrophy, in the later stages. 

 There may be fluidity and detachment of the vitreous 

 and cataract of the lens. 



Symptoms. — Take the tension, gently palpating 

 with finger tips, using both hands, and it may be 

 any thing, i. e., -f or — . Palpate through the sclera 

 back of the cornea. Cases will be met with where 

 the tension will be stony in its degree of hard- 

 ness. Haziness of the cornea is usually present, and 



