Lobar pneumonia now ranks with tuberculosis in respect to mortality rate. In the registration area of the United States, the annual toll of deaths for each of these infectious diseases is approximately 100,000. While in both instances this figure is considerably lower than it was twenty years ago, it is still high enough to make them by far the most deadly of the infectious diseases. It is interesting that both of these diseases should be largely pulmonary. This fact suggests that there may be something in the anatomic structure of the lung which renders pulmonary infection difficult to control. Pneumonia is an acute disease and tuberculosis a chronic one, but in neither case has specific therapy met with much success.
Attempts to work out a successful serum treatment in pneumonia date from the discovery that lobar pneumonia was a pneumococcal infection, but not until recently have any encouraging results been