MICIi.OBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 77 1 



The temperature range of the influenza bacterium is about 26° to 41°. It is aerobic. 

 It grows on artificial media only, in the presence of blood pigment. On plain agar, 

 glycerin agar, or blood serum with a thin layer of rabbit or human blood the colonies 

 in twenty-four hours are very small, round and transparent, and remain discrete 

 unless very thickly sown. The center of older colonies may acquire a yellow-brown 

 color. In blood broth growth occurs quite readily if the medium is used in thin 

 layers. It shows very much less resistance than the majority of non-spore-bearing 

 bacteria. It is destroyed at 60° within about one minute. It is especially sensitive 

 to drying. 



The bacterium gains entrance tlirough the mouth and nose and finds 

 suitable soil in the mucous membrane of the respiratory passage. The 

 toxaemia is due to absorption from this site rather than to the presence 

 of the bacteria in the blood. 



The bodies of the bacteria are distinctly pyogenic. 



Secondary infections are prone to follow upon influenza so that 

 abscess, gangrene of the lung, and empyema are not infrequent. 



Influenza bacteria have been found in pneumonia, otitis media, and 

 meningitis. 



Immunity after natural infection is transitory. 



The organisms are eliminated through the gates of entrance. Infec- 

 tion is for the most part direct, and follows close contact with a patient 

 or carrier. 



The bacteria are said to persist for many years in the bronchial 

 secretions of convalescents and healthy individuals. 



Therapeutically there is no specific measure for the control of this 

 disease. Remembering that the infective agent is ejected during the 

 coughing and speaking of the patient and is present in great numbers 

 in the sputum, personal hygienic measures in both patient and contact 

 should prove very effective. 



Whooping Cough* 

 ' Bacterium pertusis 



Whooping cough accounted for the death of 4,856 children in the 

 United States in 1907. The causative agent, according to Bordet and 

 Gengou, is an influenza-Hke bacillus. 



It is a non-motile coccoid bacillus, stained faintly by 'aniline dyes 

 and Gram-negative. It is distinguished from the influenza bacillus by 



• Prepared by Edward Fidlar. 



