262 DISEASES OF THE HOESE. 



sional sponging out of the nose with warm water, and the application 

 of the same on the face. Another remedy is to feed warm mashes of 

 wheat bran from a nosebag, so that the relaxing effects of the water 

 vapor may be secured. 



The two lachrymal openings, situated at the inner angle of the eye, 

 may fail to admit the tears by reason of their deviation outward in 

 connection with eversion of the lower lid, or by reason of their con- 

 striction in inflammation of the mucous membrane. The lachrymal 

 sac, into which the lachrymal ducts open, may fail to discharge its 

 contents by reason of constriction or closure of the duct leading to the 

 nose, and it then forms a rounded swelling beneath the inner angle 

 of the eye. The duct leading from the sac to the nose may be com- 

 pressed or obliterated by fractures of the bones of the face, and in 

 disease of these bones (osteosarcoma, so-called osteoporosis, diseased 

 teeth, glanders of the nasal sinuses, abscess of the same cavities) . 



The narrowed or obstructed ducts may be made pervious by a fine 

 silver probe passed down to the lachrymal sac, and any existing 

 inflammation of the passages may be counteracted by the use of steam- 

 ing mashes of wheat bran, by fomentations or wet cloths over the face, 

 and even by the use of astringent eyewashes and the injection of 

 similar liquids into the lachrymal canal from its nasal opening. The 

 ordinary eyewash may be used for this purpose, or it may be injected 

 after dilution to half its strength. The fractures and diseases of the 

 bones and teeth must be treated according to their special demands 

 when, if the canal is still left pervious, it may be again rendered 

 useful. 



EXTERNAL OPHTHALMIA, OR CONJUNCTIVITIS. 



In inflammation of the outer parts of the eyeball the exposed vas- 

 cular and sensitive mucous membrane (conjunctiva) which covers the 

 ball, the eyelids, the haw, and the lachrymal apparatus, is usually the 

 most deeply involved, yet adjacent parts are more or less implicated, 

 and when disease is concentrated on these contiguous parts it consti- 

 tutes a phase of external ophthalmia which demands a special notice. 

 These have accordingly been already treated of. 



Causes. — The causes of external ophthalmia are mainly those that 

 act locally — blows with whips, clubs, and twigs, the presence of for- 

 eign bodies like hay seed, chaff, dust, lime, sand, snuff, pollen of 

 plants, flies attracted by the brilliancy of the eye, wounds of the 

 bridle, the migration of the scabies (mange) insect into the eye, 

 smoke, ammonia rising from the excretions, irritant emanations from 

 drying marshes, etc. Eoad dust containing 'infecting microbes is a 

 common factor. A very dry air is alleged to act injuriously by drying 

 the eye as well as by favoring the production of irritant dust ; and the 

 undue exposure to bright sunshine through a window in front of the 



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