iv MICROBES SIMULATING THE B. PESTIS 57 



nitis, suppurations — they prove virulent to the guinea-pig. 

 There is one character by which these pathogenic coli-like 

 microbes can be at once distinguished, viz. a particle of a 

 colony examined in the hanging drop shows motile bacilli. 

 Further, inoculated cutaneously into mice or rats or 

 guinea-pigs they cause no effect, also subcutaneously into 

 rats they are non -pathogenic ; but subcutaneously injected 

 in fair amounts into the groin of guinea-pigs they cause 

 gelatinous, often sanguineous, infiltration, leading in some 

 instances to death of the animal within thirty to forty-eight 

 hours. The bacilli of the culture as also of the subcutaneous 

 infiltration show motility, and, after suitable staining in 

 film specimens, more or less marked bipolar staining. 



I will here give an instance in which coli-like microbes 

 present in diseased tissues (of man) had, on account of 

 their bipolar staining in film specimens, and on account 

 of their virulence for the guinea-pig, been erroneously 

 declared as B. pestis. 



A case of acute broncho-pneumonia occurred in hospital 

 in a certain city — A. In the routine work of the patho- 

 logist of the hospital the sputum of the case showed in 

 stained film specimens a large number of bacilli with 

 marked bipolar appearance. This occurred at a time 

 when not only in several ports of England single 

 cases of plague had been imported, but there had also 

 occurred several cases of plague in a port B. in fairly close 

 and frequent communication with A. Cultures of the 

 sputum and also injection of a guinea-pig were made. 

 The guinea-pig died after a few days with sanguineous 

 tumour. In this sanguineous exudation were crowds of 

 bacilli, which in film specimens showed bipolar staining. 

 Diagnosis was made : Plague pneumonia. 



