236 BACTERIOLOGY FOR NURSES 



two parts of agar to one part of blood. In fact, on no other culture 

 medium so far employed has cultivation been possible. If pus 

 obtained from a lesion is smeared over the medium minute gray 

 transparent colonies will usually appear after forty-eight hours 

 incubation. 



Pathogenesis. The disease appears as an acute inflammation 

 followed in one or two days by pustule formation. The pustule 

 soon ruptures and a small depressed ulcer remains, around which 

 other pustules and ulcers develop and necrosis spreads rapidly. 

 The lymphatics in the groin become swollen, and later " buboes " 

 or abscesses result. The lesions are usually upon the genitals 

 and infection is most frequently conveyed from one person to 

 another by direct contact. The chancre differs from that of 

 syphilis in that there is no induration. 



So far animal inoculations have been without result except in 

 monkeys. The causal relationship of the organism to the disease, 

 however, was established by Tomasczewski, who produced the 

 lesions by the injection of a pure culture into a human body. 



(2) HEMORRHAGIC SEPTICEMIA GROUP 



A group of bacilli have been described all of which have similar 

 characteristics and which give rise in the lower animals to an acute 

 septicemia usually with hemorrhagic areas in the subcutaneous 

 tissues and internal organs. The bacilli are short, non-motile, 

 Gram negative, and they do not form spores; growth is scanty 

 on gelatin and the medium is not liquefied. . They have been 

 found in rabbit septicemia, chicken cholera, swine plague, and a 

 similar infection in cattle. 



Morphologically and culturally the organisms isolated from the 

 different sources appear identical. They vary, however, in their 

 degree of virulence for the different animal species. B. Avisepticus 

 produces a septicemia rapidly fatal in fowls but much less severe 

 in pigs, sheep, and horses. B. Suisepticus is moderately pathogenic 

 for fowls, but in young pigs it produces a broncho-pneumonia, to 

 which they usually quickly succumb. Evidence points to a close 



