INFLUENZA. 567 



Pneumonic foci which develop during influenza Mixed 



, . . Infections. 



frequently snow the pneumococcus, and sometimes 

 the streptococcus or the bacillus of Friedlander in 

 addition to the influenza bacillus, and similar 

 mixed infections occur in pleurisy and in middle- 

 ear diseases. Influenza may be superimposed on 

 other infections; individuals suffering from pul- 

 monary tuberculosis are particularly susceptible to 

 influenza, and in them the prognosis is unfavor- 

 able. 

 The disease is transmitted directly from man to Transmission, 



_ _ J . Infection 



man and. chiefly, it is supposed, by means of in- Atria and 



i j l J- -c u- u n j Prophylaxis. 



fected droplets of sputum which are expelled in 

 coughing and sneezing. Obviously kissing affords 

 opportunity for infection. Infection by indirect 

 contact is of less importance because of the rapid 

 death of the bacillus after it leaves the body, but 

 living germs may well be disseminated by soiled 

 handkerchiefs or other contaminated linen. Dust 

 infection possibly is of minor consequence. Chronic 

 influenza in which the bacilli may persist in the 

 bronchi for weeks, and cause recurrent acute at- 

 tacks, is of importance for the maintenance of an 

 epidemic. In tuberculous cavities the bacilli may 

 flourish for long periods. 



Primary infection takes place in the upper res- 

 pitory passages, and the disease extends readily 

 from one surface to another, as from the nose to 

 the pulmonary tissue. Infection of the ear usually 

 is a complication of pharyngeal or pulmonary in- 

 fection. Occasionally an influenza conjunctivitis 

 is found without other localization. "Primary" 

 infection of other organs, as the brain and perito- 

 neum, are metastatic, although the original focus 

 or atrium may not be observed. 



