GROUP OF SPORE-BEARING ANAEROBES 



361 



and brittle. Hemorrhages are generally to be found in the sub- 

 cutaneous tissues. The disease has been noted in man, and is 

 not uncommon in the horse and the sheep. It occurs more rarely 

 in cattle. It is a typical wound infection. 



Immunity. Animals which recover from an infection are found 

 to be thereafter immune. The organism is also known to produce 

 a leukocidin, which destroys 

 white blood-cells. Aside from 

 these facts, little is known rela- 

 tive to the factors determining 

 immunity in this disease. 



Transmission. The organ- 

 ism usually gains entrance 

 through wounds, although the 

 possibility of a cryptic infec- 

 tion, such as is claimed to occur 

 in tetanus, should not be 



Fig. 152. Bacillus cedematis, dextrose 

 gelatin culture (Giinther). 



ignored. In man the disease 

 has been known to occur fol- 

 lowing injections in which an 

 unclean hypodermic syringe was used, and a case has been reported 

 in which the organisms were believed to have gained entrance to the 

 body through the intestinal ulcers of typhoid fever. Infection 

 may follow delivery, castration, shearing of sheep, use of unclean 

 syringes or instruments, or dirty wounds of any kind. 



Bacillus welchii 



Synonyms. Bacillus aerogenes capsulatus; B. phlegmones em- 

 physematosce ; B. enteritidis sporogenes; Bacterium welchii; B. 

 perfringens; Granulobacillus saccharobutyricus immobilis; B. anaero- 

 bicus cryptobutyricus ; B. cadaveris butyricus; B. emphysematis 

 vagina?. 



Disease Produced. Gaseous edema in man. 



Welch, in 1892, described Bacillus aerogenes capsulatus from 

 the body of a man who died from an aortic aneurysm. The in- 

 ternal organs and subcutaneous tissues showed considerable 

 emphysema. Since that time it has been repeatedly isolated in 

 Europe and America. 



