510 INFECTION AND IMMUNITY. 



may develop. The kidneys and liver usually show 

 acute degenerations. 



Diplococcus pneumonia occurs as a complication 

 in typhoid, diphtheria, tuberculosis, influenza, ery- 

 sipelas and other infections, the organism of the 

 primary infection also being found in the lungs. 

 Not infrequently staphylococci,, streptococci, Mi- 

 crococcus catarrhalis, or the bacillus of Friedland- 

 er,' are found with the pneumococcus, the latter 

 being the predominating organism. Recent work 

 from Phipps' Institute (Flick, Eavenell and Er- 

 win) suggests that the pneumococcus may be an 

 exciting cause of pulmonary hemorrhage in the 

 tuberculous. 



prophylaxis. Prophylactic measures are largely of an individ- 

 ual character. One should not come in contact un- 

 necessarily with those suffering from pneumonia. 

 The susceptible should be guarded against expos- 

 ure; pneumonia should be considered as a conta- 

 gious disease, the patients should be isolated, the 

 sputum disinfected, and rooms cleaned with moist 

 antiseptics rather than by dusting and sweeping; 

 the sick room should be flooded with sunlight, and 

 the mouths of convalescents disinfected. Expecto- 

 ration in public places should be limited. To what 

 extent the dust-laden atmosphere which prevails 

 in most of our large cities is a factor in causing 

 pneumonia is unknown. Vaccination is not yet 

 an established procedure. 



immunity It is probable that the susceptibility of man 

 d lability" varies greatly. Under equal conditions of expos- 

 ure not all contract pneumonia, and an individual 

 who eventually contracts the disease may have 

 undergone many similar exposures previously. 

 Klemperer introduced a culture of the pneumococ- 



