Meningo — Encephalitis. Staggers. 99 



congestions and inflammation in canine distemper, equine con- 

 tagious pneumonia, laminitis, and angina. 



Among mineral poisons, lead is notorious as a cause of acute 

 cerebral disorder often leading to inflammation. Other mineral 

 poisons like arsenic and phosphorus ma}' lead to encephalitis 

 symptomatic of gastro intestinal irritation, or caused b}' the^toxic 

 products of indigestion. 



Rapidly growing tumors, like cholesteatomata, are liable to 

 induce recurrent attacks of enceplialitis in connection with 

 periodic irritation. 



Finally parasites in the cranium are sufficient causes of at- 

 tacks. In the New York State Veterinary College Museum is the 

 brain of a cat with a nematoid wound round the hypophysis. In 

 equine subjects suffering from the strongylus armatus the larval 

 worm or clots cau.sed by its presence in other arteries sometimes 

 invade the encephalic blood vessels causing disturbances of the 

 circulation, embolism, inflammation or degeneration. (Albrecht, 

 Von Heill). The larvae of the oestrus has also been found in the 

 brain substance producing inflammatory or degenerative foci 

 (Briickmiiller, Megnin, Siedamgrotzky). Their presence in the 

 nasal sinuses at times cause encephalitis by contiguit}'. The ces- 

 toid worms, coenurus in sheep and other ruminants, and cysti- 

 cercus in swine, find their natural larval habitat in the brain and 

 by their movements produce mcjre or less congestion and inflam- 

 mation. Cases of ccenurus in the horse have been described by 

 Rousset, Frenzel, Zundel, and Schwanefeldt. 



Symptoms. The symptoms of uncomplicated meningitis on the 

 one hand and encephalitis on the other are rarel}' seen, the 

 disease usually implicating more or less both brain and meninges, 

 in a common inflammation or the symptoms of the one involving 

 those of the other through proximity or interdependence of func- 

 tion. And yet in traumatic lesions of the cranial walls, the 

 symptoms may be those of pure meningitis, and in thrombosis, 

 embolism or parasitism of the brain, and in certain tumors they 

 may be those of 'simple encephalitis. The distinction consists 

 largely in the predominance of fever, hyperaesthesia, active de- 

 lirium and convulsions in meningitis, and especially in its earlier 

 stages ; and the prominence of dullness, stupor, somnolence, mus- 

 cular weakness, paralysis, anaesthesia, coma, and the clouding of 

 special senses, with much less pronounced febrile reaction, or 

 vascular excitement in encephalitis. 



