54 OMENTAL PLAGUE chap. 



happens, the analyst proceeds at once, without examina- 

 tion of fresh specimens, to make stained film specimens, he 

 would notice that the bacilli, at any rate some of them, 

 show distinct bipolar staining, that they are Gram-negative, 

 and that in shape and size they resemble the B. pestis. 

 Diagnosis of " plague " under the conditions of analysis 

 just detailed might seem justified, but all the time the 

 analyst was working with the common Proteus vulgaris. 

 A gelatine plate or gelatine tube subcultured from the 

 agar plate or from the subcutaneous exudation of the 

 second guinea-pig would produce the typically liquefying 

 Proteus vulgaris. 



I have in the foregoing described the results, not of an 

 hypothetical, but of the actual analysis of the case. This 

 proteus, as is highly probable, might have been picked up 

 from the surface of the (dirty) skin of the axilla while 

 gland juice was taken from the gland, or it might have 

 been in the gland itself ; at any rate the microbe was 

 undoubtedly Proteus vulgaris. 



Or take other instances. Repeatedly it occurred that 

 dead rats found in the hold of a ship were sent for ex- 

 amination. These ships had touched at or came from an 

 infected country. Although no cases of plague had 

 occurred on board ship, nor had any diseased or dead rats 

 been found during the voyage, nevertheless when dis- 

 charging cargo one or other dead rat had been found. 

 In other cases, the ship having had a case of plague 

 during the voyage, or a case of plague having occurred on 

 landing, and the ship having been subjected to disinfection 

 by the Clayton or other process, dead rats in numbers 

 would then of course be found, and some submitted to 

 analysis. 



