DISEASES OF THE EYE AND ITS APPENDAGES. 365 



or chisel. The margin of the orbit may be crushed at any point and 

 cause periorbital abscess, or necrosis may result from the presence of a 

 splinter of bone or the excessive destruction of bone. In all cases of 

 fracture the animal should be taken out of the herd and kept by itself 

 until the injured part has had time to heal. 



NECROSIS OF THE BONY ORBIT. 



As the result of fracture of the margin of the orbit a part of the 

 injured bone may become necrosed (dead), and periostitis and periorbital 

 abscess will follow as a consequence. The discovery of this disease will 

 at first resemble abscess, but on making an examination with a probe after 

 the abscess is open we will find the bone rough and brittle at the point 

 of disease. The discharge will have a peculiar fetid odor, and is often 

 mixed with blood. 



Treatment. The aifected bone must be laid bare and all diseased por- 

 tions removed by scraping, or if necessary with saw or chisel, disre- 

 garding the extent of the injury or the size of the wound necessary to 

 be inflicted. A large portion of the bony orbit may be removed with- 

 out serious danger to the eye, provided the eyeball itself has not been 

 previously affected by the disease or involved in the original injury. 



TUMORS OF THE ORBIT. 



A fungus tumor of the eyeball or orbit occasionally appears, which 

 is designated fungus ha'matode*. This may arise without any appre- 

 ciable cause, or as the result of a wound. It frequently commences 

 within the eyeball as a small red mass, eventually bursts through, and 

 pushes its way outside of the orbit as a large dark red mass, bleeding 

 at the slightest touch. It has a peculiar fetid odor, and early in its 

 appearance destroys sight, involving all the contents of the orbit, not 

 infrequently the bony wall itself. 



Unless the tumor is totally removed in its early stage of growth, 

 together with the eyeball, the disease will eventually cause emaciation 

 and death of the animal. The enucleation of the eyeball should not be 

 undertaken by any one unacquainted with the anatomical structures 

 involved in such an operation. When the operation is performed early 

 enough the result is generally satisfactory. 



Bony tumors of the orbit are occasionally present in cattle, the result 

 of bruises, fractures, etc. They may em-roach UJMHI the contents of 

 the orbit, causing paralysis of the optic nerve the condition known 

 as amatirosiH or by pressure upon the imstcrior surface of the eyeball 

 force it forward, or produce atrophy (shrinking). They may displace 

 the eye in any direction, with or without disturbing vision. 



Fibrous tumors growing within the orbit will produce symptoms simi- 

 lar to those of bony tumors. 



Treatment. When the outlines of the tumor, whether fungoid, lK>ny, 

 or fibrous, can be detected, an operation for its removal should be Under- 

 taken as soon as the sight of the eye is in any manner disturbed. 



