326 BACTERIOLOGY. 



abscess formation. Bacilli are found in fatal cases 

 to have penetrated from the bronchial tubes not only 

 into the peribronchitic tissue, but even to the sur- 

 face of the pleura, and rarely they have been obtained 

 in pure cultures in the purulent exudation. The pleu- 

 risy which follows influenza, however, is usually a 

 secondary infection, due to the streptococcus or pneu- 

 mococcus. Ordinarily influenza runs an acute or sub- 

 acute course, and not infrequently it is accompanied by 

 mixed infections, with the pneumococcns and the strep- 

 tococcus. Pfeiffer was the first to draw attention to 

 certain chronic conditions depending upon the influenza 

 bacillus. According to this observer, these bacilli may 

 be retained in the lung tissue for months at a time, 

 remaining latent awhile, and then becoming active 

 again, with a resulting exacerbation of the disease. 

 Consumptives are particularly susceptible to attacks of 

 influenza. Williams, in the examination of washed 

 sputa in cases of pulmonary tuberculosis, has on numer- 

 ous occasions found abundant influenza bacilli, and this 

 in the summer, when no influenza was known to be 

 present in New York. Taken together with Pfeiffer's 

 results in Berlin, this indicates that at all times of the 

 year many consumptives carry about with them influ- 

 enza bacilli, and that very likely many healthy persons 

 also harbor a few. Given proper climatic conditions, 

 we have at all times the seed to start an epidemic. 



The influenza bacillus does not occur, as a rule, in 

 the blood. According to Pfuhl and Nauwerck, the 

 influenza bacilli have been found in the interior organs 

 and the brain, but these observations require further 

 confirmation. So far as positive results have shown, 

 influenza would seem to be a local infection confined to 



