98 ORIENTAL PLAGUE ' chap. 



The plate cultures yielded colonies which in their 

 aspect differed in no way from those of B. pestis. Under 

 the microscope, however, the young colonies were com- 

 posed of bacilli which were less cylindrical than the 

 typical plague bacilli, most of them being more like oval 

 cocci. Subcultures were made on agar surface, on 

 gelatine, and in broth. These subcultures yielded growths 

 indistinguishable from those of B. pestis, except that on 

 gelatine the colonies were more translucent and less 

 granular than those of the typical B. pestis ; on agar the 

 growth was of the typical grey, filmy, viscid character. 

 In staining power no difference between Dr. Edington's 

 bacilli and those of typical B. pestis could be detected. 



Intraperitoneal injection of the guinea-pig with the 

 culture obtained direct from Dr. Edington yielded no 

 result. But injection of a large dose (^th-^th) of a fresh 

 subculture of this Cape bacillus, on agar or on gelatine, 

 into the peritoneum of a guinea-pig caused within twenty- 

 four hours death of the animal with typical plague 

 manifestations. The peritoneal cavity contained grey, 

 thick, viscid exudation, and the serous covering of the 

 intestines was much inflamed. This exudation was one 

 mass of oval bacilli, some arranged as chains. Film 

 specimens stained in dilute fuchsin showed the bacilli 

 with the characteristic bipolar appearance. Subcutaneous 

 injection into guinea-pigs and rats of a fairly large dose of 

 the peritoneal exudation (^-^ c.c.) produced in them the 

 typical symptoms of plague with the characteristic bubo. 



I have, therefore, no hesitation in concluding that the 

 cultures sent by Dr. Edington were those of B. pestis of 

 somewhat attenuated and of atypical character. The 

 atypical nature of the microbe was indicated chiefly in the 



