478 PATHOGENIC MICROORGANISMS 



valescence, great care in mouth disinfection and control of this feature 

 before patients are returned to their homes should be practiced. 



Secondary Pneumonias. In Secondary pneumonias we are dealing 

 with an entirely different sanitary problem. While pneumonia may be 

 secondary to a large number of different diseases, the only ones which 

 arc of distinct epidemiological importance in this connection are 

 influenza and measles. There is no epidemic of measles or influenza in 

 which there are not, at the same time, a considerable number of pneu- 

 monias, and these pneumonias are more apt to take the form of the 

 lobular or broncho-pneumonic type. In both of these diseases there 

 is a certain amount of inflammation of the bronchial mucous mem- 

 branes which seems to render the patient particularly susceptible to 

 secondary infection with virulent pneumococci and streptococci. The 

 peculiar susceptibility of patients with measles and influenza to pneu- 

 monia cannot be explained purely on the basis of the mild bronchial 

 inflammation which may be considered distinctly an integral part of 

 these diseases themselves. There is a depression of resistance to pul- 

 monary infection which is quite out of proportion to that which accom- 

 panies many other conditions in which bronchitis and catarrhal 

 inflammation of the upper respiratory tract are common. Measles 

 epidemics are fortunately uncommon in urban communities, but may 

 assume dangerous proportions in army camps, institutions, schools, 

 etc. The mortality of uncomplicated measles is low, but the high mor- 

 tality which so often accompanies epidemics of measles is almost 

 entirely a pneumonia mortality. In one such epidemic which occurred 

 at Camp "Wheeler during the early stages of our entrance into the 

 War, the mortality of measles pneumonias was 29 per cent. Sanitary 

 measures under such conditions include, of course, those aimed at the 

 prevention of the primary disease, as well as attempts at preventing 

 the secondary pneumonias with which we are here particularly con- 

 cerned. But for the saving of life, the sanitary attention to the pre- 

 vention of the secondary complications is by far the more important 

 of the two. With the prevention of the primary disease we deal with 

 in the chapter on Measles, but a few drops may be said in this place 

 concerning the important measures which should be taken during 

 measles epidemics to prevent the occurrence of secondary pneumonias. 

 The principles of such measures are twofold, in the first place to pre- 

 vent the case which is coughing and spitting from transferring its 

 mouth streptococci and pneumococci to others. There should be the 



