216 TEXT-BOOK OF BACTERIOLOGY. 



II. BACILLUS OF MALIGNANT (EDEMA. 



The great majority of questions more or less connected with the 

 origin of anthrax could not he answered with certainty until recent 

 methods had rendered it possible to judge the properties of micro- 

 organisms with exactitude, and until anthrax disease could toe dis- 

 tinguished from other affections which resemble it at first sight, 

 and which are caused by similar species of bacteria. 



One of the latter has become more exactly known by the inves- 

 tigations of Koch; we refer to the bacilli of malignant oedema, as 

 he has called them, and which are probably the same which Pasteur 

 discovered among his "septicemic" and described as "vibrions 

 septiques." 



Malignant oedema has recently been observed also in human 

 subjects in connection with compound fractures of bones and deep 

 wounds, as also in subcutaneous injections. It produces an extensive 

 emphysema of the skin, putrefaction and oedematous softening of 

 the superficial muscles; in most cases death ensues in a few days. 

 For these cases we must suppose that the injured parts had in 

 some way come into contact with germs of malignant oedema — a 

 supposition all the more probable since these germs are very widely 

 diffused in nature. 



At least we can easily produce the disease in susceptible animals 

 with the most varied material of infection. Various decomposing 

 matters, foul water, the dust from between the planks of flooring, 

 the blood of animals that have been suffocated, and particularly the 

 upper layers of garden earth, all serve excellently for this purpose. 



If we take a moderate quantity (as much as can be raised on 

 the point of a knife) of the latter material, and place it in a pouch 

 under the skin of a Guinea-pig-'s or rabbit's abdomen, the animal 

 usually perishes within twenty-four or forty-eight hours, and on 

 examination oedema bacilli are found to be the cause of death. 



These are slender, thin rod-cells, considerablj' narrower than the 

 anthrax bacteria, with rather sharply-pointed or rounded ends. In 

 cultivation, as in the bodies of animals, they tend to unite in long' 

 threads which are often curiously bent in the form of a bow. 



The redema bacilli have lively motile power and are among 

 the rod-cells species in which R. Pfeiffer has succeeded, by the aid 

 of LofHer's staining process, in showing the existence of lateral 

 flagella. In the hanging drop, the faculty of locomotion g-enerally 

 ceases after a short time, since this bacillus, as will presently be' 

 seen, is killed by the oxygen of the air. 



At a somewhat high temperature, above 20° C, sporulation 



