EXPERIMENTAL INOCULATION. 399 



in about twenty -four to forty -eight hours. There is an 

 intense inflammatory oedema around the site of inoculation, 

 which extends over the wall of the abdomen and thorax. 

 The skin and subcutaneous tissue are infiltrated with a 

 reddish-brown fluid and softened ; they contain bubbles of 

 gas and are at places gangrenous. The superficial muscles 

 are also involved. These parts have a very putrid odour. 

 The internal organs are congested, the spleen soft but not 

 much enlarged. In such conditions the bacillus of malig- 

 nant oedema, both in short and long forms, will be found 

 in the affected tissues along with various other organisms. 

 Spores may be present, especially when the examination is 

 made some time after the death of the animal. If the 

 animal is examined immediately after death, a few of the 

 bacilli may be present in the peritoneum and pleurae, 

 usually in the form of long motile filaments, but they are 

 almost invariably absent from the blood. A short time after 

 death, however, they spread directly into the blood and various 

 organs, and may then be found in considerable numbers. 



Subcutaneous inoculation with pure cultures of the 

 bacillus of malignant oedema produces chiefly a spreading 

 bloody oedema, the muscles being softened and partly 

 necrosed ; but there is little formation of gas, and the 

 putrid odour is almost absent. 



When the bacilli are injected into mice, however, they 

 enter and multiply in the blood stream, and they are found 

 in considerable numbers in the various organs, so that a 

 condition not unlike that of anthrax is found. The spleen 

 also is much swollen. 



The virulence of the bacillus of malignant oedema 

 varies considerably in different cases, and it always be- 

 comes diminished in cultures grown for some time. To 

 produce a fatal disease, a relatively large number of the 

 organisms is necessary, and these must be introduced 

 deeply into the tissues, inoculation by scarification being 

 followed by no result. A smaller dose produces a fatal 

 result when injected along with various other organisms 

 (bacillus prodigiosus, etc,). 



