44 OEIENTAL PLAGUE chap. 



examination, the following conclusions may be drawn. 

 According to this analysis we may group the cases in — 



(1) Cases which already on microscopic examination 

 of stained film specimens alone may be pronounced to 

 be most probably plague, and therefore the microscopic 

 examination is able to justify the epidemiologist's and 

 clinician's preliminary diagnosis of plague, or at any rate 

 make it highly probable that the cases are true plague ; 

 such are Case 2 (pneumonic plague) and Case 3 (bubonic 

 plague). Culture in surface agar plates and experiment 

 on guinea-pigs clinched the diagnosis in twenty-four hours. 



(2) Cases in which the microscopic examination of 

 stained film specimens could not venture to make any 

 diagnosis, but in which culture in agar surface plates and 

 animal experiment enabled diagnosis of B. pestis to be 

 made after twenty-four hours or later; such were Case 1 

 (abscess in groin) and Case 4 (bubo in groin). 



(3) Cases in which film specimens and twenty -four 

 hours' agar culture could negative plague ; in some of 

 these the glandular swelling, or the suppurating bubo, was 

 clearly caused by infection with Staphylococcus pyogenes 

 aureus, and in others (Case 7) the fatal pneumonia was 

 caused by B. injluenzce. 



(4) There is a fourth category of cases, however, in 

 which the microscopic examination and the culture of 

 material taken from a glandular swelling (associated with 

 fever) yielded no bacteria of any kind : cases, that is, which 

 already on this evidence could be negatived as due to 

 plague. I have had several such instances ; materials of 

 these were submitted for analysis because, notwithstanding 

 the want of epidemiological evidence, the medical officers 

 of health quite laudably did not wish to incur any risk of 



