CHAPTER XxX. 
INFLUENZA BACILLUS. 
AFTER numerous unsuccessful attempts during the 
epidemic of 1889 and succeeding years to discover the 
specific cause of influenza, Pfeiffer succeeded in isolating 
a bacillus (1892) from the purulent bronchial secretion 
of patients suffering from epidemic influenza which he 
Fra. 40. 
Influenza bacilli. > 1100 diameters. 
showed was the probable cause of the disease. This 
discovery has since been confirmed by many observers, 
the results of whose researches give us reason to believe 
that this bacillus is the chief emological! factor in the 
production of influenza. 
