CHAPTER X 



INFLUENZA 



C PI DEM 1C influenza ("la grippe") is an infec- 

 " tious disease due to a minute bacillus discovered 

 by the German bacteriologist Pfeiffer in 1892. This 

 bacillus is found in great numbers in the purulent 

 bronchial secretion coughed up by persons suffering 

 from influenza and the disease is propagated by con- 

 tact with the sick and with articles infected by them, 

 just as is the case in diphtheria, or whooping-cough. 

 The rapid extension and wide prevalence of the dis- 

 ease is due to the facts that persons of all ages are 

 susceptible, and that isolation of the sick and disin- 

 fection of sputa are rarely practised, on account of its 

 comparatively mild character. Nevertheless, the dis- 

 ease is attended with considerable danger, especially 

 for old persons or those in feeble health ; and it is the 

 direct or remote cause of many deaths. The offi- 

 cial records of Prussia for 1892 show a mortality from 

 this disease of 15,911, of whom over half were more 



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