BACILLUS BOTULINUS 393 



When the bacilli are injected into mice, however, they enter 

 and multiply in the blood stream, and they are found in con- 

 siderable 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 con- 

 siderably in different cases, and it always becomes 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 scari- 

 fication being followed by no result. A smaller dose produces a 

 fatal result when injected along with various other organisms 

 (bacillus prodigiosus, etc.). 



Immunity. Malignant oedema was one of the first diseases 

 against which immunity was produced by injections of toxins. 

 The filtered cultures of the bacillus in sufficient doses produce 

 death with the same symptoms as those caused by the living 

 organisms, but a relatively large quantity is necessary. Chamber- 

 land and Roux (1887) found that if guinea-pigs were injected 

 with several non-fatal doses of cultures sterilised by heat or freed 

 from the bacilli by filtration, immunity against the living organism 

 could be developed in a comparatively short time. They found 

 that the filtered serum of animals dead of the disease is more 

 highly toxic, and also gives immunity when injected in small 

 doses. These experiments have been confirmed by Sanfelice. 



Methods of Diagnosis. In any case of supposed malignant 

 oedema, the fluid from the affected tissues ought first to be 

 examined microscopically, to ascertain the characters of the 

 organisms present. Though it is not possible to identify ab- 

 solutely the bacillus of malignant oedema without cultivating it, 

 the presence of spore-bearing bacilli with the characters described 

 above is highly suspicious (Fig. 1 29). In such a case the fluid 

 containing the bacilli should be first exposed to a temperature 

 of 80 C. for half an hour, and then a deep glucose agar tube 

 should be inoculated. In this way the spore-free organisms are 

 killed off. Pure cultures may be thus obtained, or this procedure 

 may require to be followed by the roll -tube method under 

 anaerobic conditions. An inoculation experiment, if available, 

 may also be made on a guinea-pig. 



BACILLUS BOTULINUS. 



The term " meat-poisoning " embraces a number of conditions 

 produced by different agents, and the relation of the bacillus of 



