iv MICROBES SIMULATING THE B. PESTIS 79 



it bleaches litmus lactose peptone without gas production, just 

 like B. Gaertner; it forms a colourless filmy growth on steamed 

 potato, like B. Gaertner ; it produces in litmus milk, like B. Gaertner, 

 at first very slight redness, this soon gives way to alkali production, 

 the litmus milk becoming blue till it is of a dark-blue slate colour, 

 the milk remaining fluid; it grows well in phenol broth, causing 

 uniform turbidity like B. Gaertner ; it produces slight indol in broth 

 after a week, like B. Gaertner; it forms "blue" colonies on Drigalski- 

 Conradi medium at 37° C. like B. Gaertner ; the colonies are smaller 

 than those of B. typhosus, but, like these latter, are at first more or 

 less round, later they are angular and at all times are raised in the 

 centre, flat at the margin, their substance finely granular: characters, 

 in short, identical with those of B. Gaertner. The bacilli are oval 

 to short cylindrical rods, actively motile in the hanging drop, and 

 Gram-negative ; they are provided with many flagella all round. 

 Of precisely the same characters, morphological, cultural, and 

 experimental — at any rate as regards the guinea-pig and mouse — is 

 the typical B. enteritidis Gaertner j and it is not necessary to specially 

 enumerate them, having described them in full just now of the 

 B. Danysz. 



The identity of the two microbes — B. Danysz and B. Gaertner — 

 has been confirmed also by the following experiments (Transactions 

 Pathological Society, 1902, p. 243): — (a) Guinea-pigs immunised by 

 B. Danysz were found immune against B. Gaertner ; (b) guinea-pigs 

 immunised by B. Gaertner were found immune against B. Danysz; 

 (c) blood serum of guinea-pigs immunised by B. Danysz agglutinates 

 equally well an emulsion of B. Danysz and of B. Gaertner ; (d) blood 

 serum of guinea-pigs immunised by B. Gaertner agglutinates equally 

 well an emulsion of B. Gaertner and of B. Danysz. Recently I have 

 carried out the same experiments with rabbits. A rabbit was 

 immunised by repeated injections of sub-fatal doses of living B. 

 Danysz, a second rabbit by repeated injections of sub-fatal doses of 

 living B. Gaertner. The blood serum of both animals was then 

 tested on emulsions of B. Danysz and of B. Gaertner and was 

 found to agglutinate emulsions of both microbes equally well. 



I therefore consider that both microbes are identical. 



Considering that acute gastro-enteritis or some forms of it have 

 been shown to have been caused by the eating of meat (beef, pork) 

 contaminated with the B. Gaertner, it seems rather a risky thing to 

 follow the recommendation of the Danysz Company, printed on their 



