264 PATHOGENIC BACTERIA. 



fatal issue. Meteorism and great tenderness of the abdo- 

 men are observed. At the autopsy a sero-fibrinous or 

 sero-purulent peritonitis is observed sometimes hemor- 

 rhagic. There is also generally a pleurisy, either serous 

 or hemorrhagic. All the abdominal viscera are con- 

 gested. The intestine is congested contains an abun- 

 dant mucous secretion. The Peyer patches are enlarged. 

 The spleen is enlarged, blackish, and often hemorrhagic. 

 In cases which are prolonged the liver is discolored. The 

 kidneys are congested, the adrenals filled with blood. 



* ' In such cases the bacillus can be found upon the in- 

 flamed serous membranes, in the inflammatory exudates, 

 in the spleen in large numbers, in the adrenals, the liver, 

 the kidneys, and sometimes in the lungs. The blood is 

 also infected, but to a rather less degree. 



"In cases described as chronic, the bacillus disappears 

 completely in from five to twenty-four hours, and pro- 

 duces but one lesion, a small abscess at the point of inoc- 

 ulation. 



4 ' Sanarelli has observed that if some of the poisonous 

 products of the colon bacillus or the Proteus vulgaris be 

 injected into the abdominal cavity of an animal recover- 

 ing from a chronic case, it speedily succumbs to typical 

 typhoid fever." 



The failure to produce a satisfactory combination of 

 symptoms by experimental inoculation into animals is 

 one of the impediments in the way of the production 

 of an antitoxin for use in human medicine. As long as 

 there can be the slightest doubt thrown upon the speci- 

 ficity of the bacillus because of the failure to produce 

 the recognized symptoms in animals, so long an anti- 

 toxic substance, if produced at all, will be rejected by 

 many in the profession. Animals can easily be accus- 

 tomed to this bacillus, and when so accustomed seem, 

 according to Chantemesse and Widal, to develop in their 

 blood an antitoxic substance capable of protecting other 

 animals. Stern has also found that in the blood of re- 

 cent human convalescents a substance exists which has a 



