IX SUSCEPTIBLE ANIMALS. 511 



vein of a rabbit cause its death in from twenty-four to thirty-six hours; 

 pathogenic also for house mice and for field mice. At the autopsy no notable 

 pathological changes are observed. The bacilli are found in blood from the 

 heart and in the capillaries of the various organs, but are not so numerous 

 as in rabbit septicaBmia; they show a special inclination to adhere to the 

 margins of the red blood corpuscles. 



BACILLUS ERYSIPELATOS SUIS. 



Synonyms. Bacillus of hog erysipelas; Bacillus des Schweine- 

 rothlauf (Loffler, Schutz) ; Bacille du rouget du pore (Pasteur) ; Ba- 

 cillus of mouse septicaemia; Bacillus murisepticus (Fliigge) ; Bacil- 

 lus des Mauseseptikamie (Koch). 



The bacillus of mouse septicaemia, first described by Koch (1878), 

 resembles so closely in its morphology, characters of growth, and 

 pathogenic power the bacillus of Schweinerothlauf of Loffler and 

 Schutz (1885) that they can scarcely be considered as distinct spe- 

 cies, although, from slight differences which have been observed, they 

 are perhaps entitled to separate consideration as varieties of the 

 same species. Fliigge, Eisenberg, Frankel, and other authors, while 

 recognizing the fact that the bacilli from the two sources closely re- 

 semble each other, apparently do not consider 

 them identical, and describe them separately. 

 Baumgarten, on the other hand, describes them 

 under one heading and considers it highly prob- 

 able that they are identical, although he also 

 admits slight differences in the morphological 

 characters and growth in culture media. These 

 differences are, however, no greater than we 

 have in artificially produced varieties of other FlG 133 _ Baclllus of 

 well-known microorganisms, and we think it mouse septicaemia in leu- 

 best to follow Baumgarten in describing them 

 under a single heading. 



Koch first obtained this bacillus by injecting putrefying blood or 

 flesh infusion, during the first days of putrefactive change, beneath 

 the skin of mice. A certain proportion of the animals experimented 

 upon contracted a fatal form of septicaemia, and the bacillus under 

 consideration was found in their blood. The bacillus of Schweine- 

 rothlauf was obtained by Loffler and by Schutz from the blood and 

 various organs of swine which had succumbed to the infectious 

 malady known in Germany as rothlauf and in France as rouget. 



Morphology. Extremely minute bacilli, about 1 v in length and 

 0.2 v in diameter. The Schweinerothlauf bacilli are described as 

 somewhat thicker and longer by Fliigge, by Frankel, and by Ei- 

 senberg, but Baumgarten states that they are somewhat more 



