180 DYSENTERY, HOG AND CHICKEN CHOLERA. 



as long twisted filaments ; (2) after the crisis of the fever is 

 reached it is seen in the leucocytes as short degenerated 

 curved rods. 



Pathogenesis. This spirillum is not pathogenic to the lower 

 animals, with the exception of the monkey. 



Blood taken from patients during the paroxysm when in- 

 oculated in other individuals may give rise to relapsing fever. 



One attack of the disease does not seem to confer immunity 

 from future attacks, but rather renders the subject more 

 susceptible. 



QUESTIONS. 



What microorganism is the cause of relapsing fever? 

 By whom and when was it discovered ? 

 Describe it. 

 How does it stain ? 

 May it be cultivated artificially? 

 Where is it found in cases of relapsing fever? 

 Is it motile ? 

 Does it contain spores? 



In what two forms is it found in the blood ? 

 For what animals is it pathogenic ? 



May blood of relapsing fever give rise to other cases of the disease by 

 inoculation ? 



Does one attack of relapsing fever confer immunity upon the subject ? 



CHAPTER XXII. 



DYSENTERY, HOG CHOLERA, AND CHICKEN CHOLERA. 

 DYSENTERY. 



Bacillus Dysentericse. 



History. This bacillus was first found in the intestinal con- 

 tents and in the visceral walls and mesenteric glands in cases 

 of acute epidemics of dysentery by Shiga, in Japan in 1898, 

 and this observation was confirmed afterward by Flexner in a 

 study of dysentery of the Philippine Islands. It seems to 

 belong to the typho-colon group. 



