250 THE MANAGEMENT AND DISEASES OF THE DOG. 



anatomy of rabies.* He remarks that the peculiar expres- 

 sion of the rabid dog's physiognomy has long been recognized 

 as an essential part of the diagnosis, and that this charac- 

 teristic indication is largely due to the dull, heavy eyes, 

 which are so commonly partially covered by the membrana 

 nictitans in rabies. Besides the malady has a tendency to 

 be accompanied by catarrh of the conjunctivse, indicated by a 

 collection of mucus in the inner canthus of the eye. Beyond 

 this, there sometimes suddenly appear circumscribed opacities 

 of the cornea, with breaking up of its texture in the centre of 

 these, and so leading to the formation of ulcers. This ulcera- 

 tion progresses so rapidly, that in some cases the substance of 

 the cornea is perforated within two days. These corneal 

 ulcerations are not, however, very common ; Siedamgrotzky 

 had only observed them in six cases, in which two or three 

 ulcers appeared in both eyes.. They are not an accompani- 

 ment of only one form of rabies, but appear in both — dumb 

 as well as furious. On a post-mortem examination, it is 

 found that the ulcer has penetrated the cornea in a conical 

 manner, and that nothing but a thin layer of fibrin, or a 

 blood coagulum in the anterior chamber, has prevented the 

 escape of the entire contents of the organ. Examined micro- 

 scopically, the corneal ulcer offers no essential difference from 

 that witnessed in distemper : moderate cell-heaping in the 

 vicinity of the ulcer, fatty degeneration of the corneal 

 elements, and opening out of the interstitial substance ; but 

 nothing otherwise characteristic. 



Siedamgrotzky at first believed that the alteration was, pro- 

 duced by mechanibal causes, but from close observation he is 

 satisfied that it may appear in the quietest animals whose 

 eyes have not been exposed to external injury. It is there- 

 fore not unlikely that an interruption in the nutrition is the 

 cause ; though not a general alteration in the nutritive func- 

 tion, but perhaps rather due originally to an alteration in the 

 trophic nerves of the eye. 

 ■ * From the "Veterinary Journal," October, 1876. 



