232 DISEASES OF THE BRAIN 



tissue at the point of inoculation, next in the blood, and then 

 in the central nervous organs. Bile, saliva, and urine do not 

 seem to be infective. The virus does not pass through fine 

 porcelain filters. Infection through the digestive tract has 

 been produced. 



Symptoms. — In horses and mules the first symptom is 

 usually an itching of the skin, especially about the head, 

 which causes the patient to rub the part often so violently 

 that it may be denuded of hair, excoriated, or even lacerated. . 

 The patients are further excitable, irritable, show dysphagia, 

 salivation, gritting of the teeth, and finally paralysis. The 

 temperature usually does not rise much above normal. 



In cattle the infection generally appears about the head, 

 lips, and nose which parts the animal rubs violently, producing 

 hemorrhage and inflammatory swellings which extend over 

 the head, throat, and sometimes the neck. The patient is 

 restless, moves its legs convulsively, keeps rubbing the head 

 against objects, or scratches it with its hind feet. Salivation 

 and inability to swallow are often noted. In some cases the 

 digestion is imparled, the patient showing flatulency. The 

 animals usually die in one or two days after the first symp- 

 toms appear. 



Course and Prognosis. — The course is rapid, the patients 

 dying within twenty-four to thirty-six hours. The prognosis 

 is bad; nearly every case dies. 



Diagnosis. — The diagnosis during the life of the patient is 

 not so easy on account of the similarity of the disease to 

 rabies. However, the patient with bulbar paralysis does not 

 show the aggressive and destructive tendencies of the rabid 

 animal and the symptom of pruritus is much more marked; 

 on postmortem Negri bodies are absent; animals inoculated 

 usually die more rapidly (rabbits in convulsions in one to 

 three days), and the saliva is not infective. 



Treatment. — Treatment is rarely of avail. It is recom- 

 mended to apply tincture of iodin to the skin lesions, and if 

 possible to so tie the animal that it cannot bite and rub itself. 

 Edematous swellings may be scarified and iodin injected. 



Believing that Rhus toxicodendron (three-leaved poison 

 ivy) or the shrub Rhus vernix might be etiological factors, 



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