536 APPLICATION OF METHODS OF BACTERIOLOGY 



at the point of operation, or by alterations very similar to 

 those produced by intra vascular inoculation, viz., death in 

 less than twenty-four hours, accompanied by redness of 

 the peritoneum and marked hyperemia and ecchymoses of 

 the small intestine, together with swelling of Peyer's patches. 

 The cecum and colon may remain unchanged or present 

 enlarged follicles. There may or may not be an accumula- 

 tion of fluid in the abdominal cavity; but peritonitis is 

 rarely present. The small intestine may contain bloody 

 mucus. 



Intravenous inoculation of rabbits may be followed by 

 similar changes, with often the occurrence of diarrhea 

 before death, which may, in the acute cases, result in from 

 three to forty hours. In another group of cases acute fatal 

 intoxication does not result, and the animal lives for weeks 

 or months, dying ultimately of what appears to be the 

 effects of a slow or chronic form of infection. For a few 

 hours after inoculation these animals present no marked 

 symptoms; exceptionally, somnolence and diarrhea have 

 been observed at this period, indicating acute intoxication 

 from which the animal has recovered. The affection is 

 unattended by fever. The most marked symptom is loss of 

 weight. This is usually progressive from 'the first or second 

 day after inoculation, with slight fluctuations until death. 



At autopsy the animal is found to be emaciated. The 

 subcutaneous tissues and the muscles appear pale and dry. 

 The serous cavities, particularly the pericardial, may con- 

 tain an excess of serum. The viscera are anemic. The 

 spleen is small, thin, and pale. Exceptionally ulcers and 

 ecchymoses are observed in the cecum, but generally there 

 are no lesions of the intestinal tract. 



The most striking and constant lesions, those most 



