248 BACTERIOLOGY FOR NURSES 



organism is motile and forms an oval spore situated in the center 

 of the bacillus. It is stained readily by the ordinary dyes. Young 

 cultures are usually Gram positive ; older ones appear to be less 

 able to retain the stain. 



Cultivation . The organism is a strict anaerobe . Growth occurs 

 at 20 C., but is more rapid and abundant at 37 C. On glucose 

 agar colonies appear of a dull white color with an irregular margin. 

 It is able to ferment glucose, lactose, and maltose and to liquefy 

 gelatin. 



Pathogenesis. A number of animals are susceptible to inocu- 

 lation with the bacilli. Subcutaneous injections produce a spread- 

 ing gelatinous edema and exudation of a blood-stained fluid, while 

 the underlying muscles become soft and partly necrosed. At- 

 tempts to produce the disease by feeding animals with the bacilli 

 or by injecting them intravenously have so far failed. In man 

 practically all infections appear to have started from fractured 

 bones or deep wounds. 



BACILLUS CHAUVEI 



Symptomatic anthrax, popularly known as " black leg " or 

 " quarter evil," is an infectious disease occurring chiefly among 

 cattle and sheep ; so far as is known infection has never occurred 

 in man. The disease was formerly confused with true anthrax. 

 The microorganisms which give rise to the two diseases, however, 

 are totally different. Morphologically and culturally B. chauvei 

 closely resembles the bacilli of malignant edema. The disease is 

 usually rapidly fatal. Edematous swelling on the thigh or shoulder 

 appears, in a few hours a considerable quantity of gas collects in 

 the tissues, and the affected muscles become almost black. Death 

 usually occurs in from one to two days. The disease is usually 

 due to wound infection with soil containing the bacilli. 



Differentiation of Wound Anaerobes. Practically all of the 

 anaerobes concerned in wound infections come from the soil and 

 originally from animal feces. The group appears to be closely 

 related. The following characteristic points of each, however, are 

 relatively constant and afford a means of differentiation. 



