80 ORIENTAL PLAGUE chap. 



advertisements, viz. to spread about in meat stores and the like, 

 cultures of the B. Danysz, with the object of destroying rats j for it 

 might happen that while the intended rat destruction fails, the meat 

 pollution and subsequent human infection might succeed. 



The rapid growth on gelatine and on agar, the motility of the 

 microbe, the production of acid and gas in glucose gelatine, and in 

 MacConkey fluid, and the inefficacy of cutaneous inoculation of 

 guinea-pigs, mice, and rats, would at once guard against the microbe 

 (B. Danysz and B. Gaertner) being mistaken for B. pestis. 



8. Bacillus pseudo-tuberculosis. — This microbe causes in the guinea- 

 pig, when injected subcutaneously or intraperitoneally, or by feeding, 

 the well known sub-acute process which in a marked manner resembles, 

 as I have fully described and illustrated in a Report to the Local 

 Government Board (1899-1900), the chronic process of "inoculation- 

 tuberculosis." The microbe, first discovered by A. Pfeiffer, was in 

 that Report fully described in its morphological, cultural, and 

 experimental characters. It was shown that the microbe differed 

 markedly in these respects from all others. I would not introduce 

 it here, were it not that in its effects on the guinea-pig it bears a 

 resemblance to subacute plague in the guinea-pig, only in this that 

 like the B. pestis of decreased virulence it causes necrotic nodules in 

 the spleen, liver, and lung, and since the guinea-pig is generally, 

 or at any rate often, used for diagnostic purposes as regards plague, 

 it may not be out of place to consider the subject here. The 

 production of necrotic nodules in the spleen, liver, and lung by 

 the B. pseudo - tuberculosis is the only ground for considering this 

 microbe in connection with plague, the two microbes being in other 

 respects totally unlike. On account of the above effect on the guinea- 

 pig, Galli Valerio and others have taken the trouble to make a com- 

 parison between the two microbes, but in my opinion he would be 

 a very superficial observer who could make a confusion between the 

 two microbes. 



In the first place as regards the effect on the animal : — 



The B. pseudo-tuberculosis is without any effect when inoculated 

 cutaneously ; neither the mouse, nor the guinea-pig, nor the rat shows 

 any symptoms of abnormal change when thus inoculated with it. 

 The rat is quite unsusceptible even when injected subcutaneously. 

 As regards the guinea-pig, the B. pseudo-tuberculosis injected sub- 

 cutaneously in the groin causes a comparatively slow process, 

 consisting in the gradual enlargement of the inguinal gland, but it 



