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 PREVENTIVE MEDICINE AND THE WAR 343 



Army show that the case morbidity rate for this disease has 

 been as follows during the different periods of the last two 

 years : 



The year of 1917 11.2 per cent. 



6 Winter months 1917-18 23.1 per cent. 



5 Summer months 1918 18.8 per cent. 



4 Autumn months 1918 34.4 per cent. 



(influenza period) 



It is not strange that once pneumonia secured a foothold in 

 patients already weakened by influenza their chances of recov- 

 ery were lessened. 



The pneumococcus has been long regarded as the chief cause 

 of pneumonia. Of this organism four distinct types are rec- 

 ognized in this country. The fourth type is in reality a 

 heterogeneous group which includes many organisms which 

 may cause pneumonia and yet whose agglutinations and other 

 reactions have not been recognized with a sufficient degree of 

 accuracy to be accepted as a means of identification. During 

 the past year, it has been impressed upon us more forcibly 

 than before that other organisms than the pneumococcus may 

 cause clinical pneumonia. The streptococcus and the staphy- 

 lococcus, at least certain varieties of these organisms, have 

 produced clinical pneumonia in our camps. One reading the 

 reports that have been sent in from army camps in all parts of 

 the country is impressed by the lack of agreement as to the 

 bacteriology which has been responsible both for influenza and 

 the accompanying pneumonia. So far as influenza is con- 

 cerned, the descriptions of the clinical symptoms agree. There 

 is no question but that the same disease clinically has existed 

 in Massachusetts, Kansas and California. In one place, how- 

 ever, the Pfeiffer bacillus, in another the streptococcus hemo- 

 lyticus and in a third some form of the pneumococcus has been 

 believed to be the cause of the disease. Suspicion has also 

 been cast upon various strains of streptococcus, the micro- 



