174 INFLUENZA. 



How does the comma bacillus stain ? 



Does it contain spores? 



Has it flagella ? 



How does it behave in the presence of oxygen? 



Is it motile ? 



What condition of the media is necessary for its growth ? 



How does it grow on gelatin plates ? In stab- cultures? On agar? In pep- 

 tone-bouillon ? 



At what temperature does it grow? 



What is its thermal death-point? 



What is the effect of cold ? Of dryness? 



How long may it be kept in a moist state ? 



How does it grow when associated with other bacteria ? 



What peculiarities of its growth are made use of in those cases to isolate it? 



What is the cause of the natural immunity of domestic animals to cholera? 



How has Koch succeeded in inoculating the lower animals through the 

 stomach ? 



What effect has inoculation of animals with cultures of the comma bacillus? 



What is the effect of intraperitoneal inoculation ? 



How are animals made immune against cholera inoculation ? 



What is the effect of the blood-serum of immunized animals on other 

 animals ? 



Where are the organisms found in cholera patients or at the autopsy in a 

 cholera case ? 



How is the cholera bacillus isolated from cholera dejecta? 



How much resisting power has the comma bacillus ? 



What is Haffkine's method of protection against cholera? 



CHAPTER XIX. 



INFLUENZA. 



Bacillus of Influenza. 



History. In 1892 Pfeiffer and Cannon independently iso- 

 lated from the bronchial and nasal secretions of cases of 

 influenza, and from the blood in some cases, a small micro- 

 organism which they believed, with apparent correctness, to 

 be the cause of the disease. 



Morphology. The bacillus so isolated may be described as 

 follows : a small, thick rod, occurring singly or in pairs, 

 stained with difficulty by the ordinary anilin dyes, but fairly 

 well with a diluted Ziehl solution or Loeffler's methylene- 

 blue ; not stained by Gram's method. The body of the rod 

 stains less well than the ends. It has no flagella and contains 

 no spores. (Plate IV.) 



