l6o BACTERIA 



Pathogenesis. Catarrhal symptoms follow the smearing of a 

 culture upon the nasal mucosa of monkeys. Pure cultures, 

 injected into the peritoneum of guinea pigs cause fatal peritonitis. 

 This bacillus was isolated by Pf eiffer during the influenza epidemic 

 of 1889 and by him believed to be the cause of the disease. Be- 

 tween that time and the pandemic of 1918 it has been found in 

 acute respiratory infections, chronic bronchitis, sinusitis, otitis and 

 meningitis, all attacks being characterized by great depression. 

 Conviction has never been obtained that it was the principal cause 

 of acute disease except for meningitis, but the bronchitis of tuber- 

 culosis has been ascribed to it on many occasions. The pandemic 

 cases of 1918 showed a high percentage of positive findings in the 

 sputum and lungs at autopsy. There was however no definite in- 

 crease in agglutinins, lysins or complement fixing anti-bodies so that 

 many have doubted its etiological relation in epidemic influenza. It 

 was present in a large percentage of cases and certainly aggravated 

 pneumonitis and sinusitis in association with streptococci. Its 

 effect seems due to an endotoxin, possibly also to some exotoxin, 

 having a definite affinity for the nervous system. It circulates 

 in the blood rarely, principally in the meningitic form and in 

 early stages of the intense general cases. 



Influenzal meningitis is more frequent than formerly or 

 at least is more often diagnosed. It can be reproduced in 

 monkeys. 



By immunizing a goat with influenza bacilli Wollstein obtained 

 a serum which has a pronouncedly favorable effect upon the 

 experimental disease in monkeys and promises some therapeutic 

 power for human beings. Its most important effect is to stimu- 

 late phagocytosis in the cerebro-spinal fluid. 



A short immunity remains after a spontaneous attack in man 

 but attempts at production of immunity by vaccines have been 

 disappointing. By the use of a mixed vaccine of influenza 

 bacilli, streptococci and pneumococci, the chance of pneumonic 

 complications seems reduced, but influenza may not be prevented. 



