iv MICEOBES SIMULATING THE B. PESTIS 69 



of the Diplococcus pneumoniae, there were present in addition, after 

 twenty-four hours' incubation, eight to twelve colonies of an altogether 

 different character. These were heaped-up whitish-grey round to 

 irregular colonies several times larger than those of the Diplococcus 

 pneumonia. Such colonies were composed of a viscid slimy material 

 which under the microscope was seen to be made up of a hyaline 

 transparent viscid interstitial or ground substance in which were 

 embedded in close juxtaposition oval to cylindrical non-motile rods, 

 thus representing a typical zooglcea mass. In stained films the bipolar 

 staining of the rods was very distinct ; so that these bacilli are not 

 dissimilar to those of Bacillus pestis. Subcultures were made from the 

 primary colonies in the different media, and in these the characters of 

 the microbe were found similar to those of microbes constituting the 

 group of bacillus of Friedlander, but with this difference, namely, 

 that the growth of the microbe in question was quicker, and that it 

 formed more pronounced viscid slimy masses. Another point which 

 distinguishes it from the B. Friedlander is that in culture it formed 

 distinct zooglcea ; that is to say, the individual bacilli are barren 

 of a separate capsule like the typical bacillus of Friedlander, but, 

 unlike that microbe, are embedded in, and held together by, a slimy 

 interstitial substance. The character, aspect, and rapid growth of 

 the colonies, as well as their mode of growth in the different media, 

 seem in general to distinguish this microbe from the B. pestis, 

 which it closely resembles as regards polar staining, and also as 

 regards length and thickness. Owing to the conspicuously slimy 

 character of the growth of this microbe I propose calling it Bacterium 

 myxoides. For the rest, in a general way it presents the characters 

 of the microbes belonging to the group of Bacillus Friedlander ; like 

 these, it does not stain by Gram's method, and does not liquefy 

 gelatine. 



A point of constant difference between this Bacterium myxoides and 

 Bacillus Friedlander is that the former, taken from the animal tissues, 

 does not under any circumstances show a capsule. This, of course, 

 can be demonstrated readily in the tissues after inoculation into 

 animals. 



Guinea-pigs and rats were, with the pure culture of B. myxoides, 

 injected cutaneously and subcutaneously. But no effect whatever 

 was hereby produced ; the animals remained well. This of course 

 proved also experimentally that the microbe was not B. pestis. 



Intraperitoneal injection of the microbe into guinea-pigs, how- 



