iv MICKOBES SIMULATING THE B. PESTIS 63 



by cutaneous inoculation, though that method ensures 

 always characteristic and positive result with B. pestis 

 and with plague material. 



In order the more effectively to discuss the nature of 

 the microbe in question, I propose to describe it under the 

 name of Bacterium Bristolense ; " bacterium " because 

 following Migula's nomenclature the microbe is non-motile, 

 and "Bristolense" because it was derived from a vessel 

 in the Port of Bristol and was not B. pestis. 



The Bacterium Bristolense is a non-motile rod, vary- 

 ing in length just as does B. pestis ; similarly it varies in 

 shape from a short oval to a cylindrical bacillus, and is 

 of about the same thickness as B. pestis. The character 

 of the microbe on gelatine, on agar, on serum, and in 

 broth is altogether similar to that of some varieties of 

 B. coli communis, and different therefore from that of 

 B. pestis. The colonies on gelatine are round, raised, 

 and moist-looking. B. Bristolense, like B. coli communis, 

 produces indol in broth ; it gives positive neutral-red 

 test; it "bubbles" (i.e. forms gas) in glucose gelatine 

 shake culture ; it forms acid in milk, and curdles this 

 medium in a few days. In these characters the microbe 

 therefore corresponds closely with B. coli, and in particu- 

 lar to a definite variety of B. coli communis. But it 

 differs from B. coli by the more rounded, thicker, and 

 whiter aspect of its colonies in gelatine plates, and its 

 thicker, whiter, and less expansive growth in gelatine 

 streak culture. After some weeks' culture on gelatine 

 there is just an indication of liquefaction, but it never 

 becomes marked. In these respects the microbe resembles 

 more the B. lactis aerogenes. B. lactis aerogenes, how- 

 ever, does not produce indol in broth, and does not give 



