CHAPTER XL 



BACILLI SPECIFICA-LLY PATHOGENIC TO MAN OR ANIMALS. 



Group A. — Amongst these a group of bacilli is first 

 to be considered which comprises several species, all of 

 which have certain characters in common, (i) All of them 

 are short oval rods, some more cylindrical than others, 

 occurring singly, in dumb-bells, or even in short chains. 



(2) They do not liquefy gelatine and do not form spores. 



(3) They produce uniform turbidity of broth already after 24- 

 36 hours at 37° C, although the amount of turbidity varies 

 in the different species, and also as regards presence or 

 absence of a pellicle. (4) They are killed by a temperature of 

 60° C. in five minutes. (5) They all produce in one or the 

 other rodent, on subcutaneous injection of small quantities of 

 culture — recent broth culture best — or of blood and tissues 

 containing the microbe, acute septicsemic infection, the 

 blood of the general circulation of the infected rodent con- 

 taining more or less copiously the injected microbe ; the 

 viscera are hyperaemic, the spleen, the liver, the lungs, the 

 kidneys, and particularly the peritoneum, containing small 

 hEemorrhages with peritoneal, pericardial, and pleural exuda- 

 tion. They differ from one another (i) in the species of 

 animals in which originally they are associated with acute 



