808 PASSIVE IMMUNIZATION SERUM THERAPY 



2. The serum must be administered in large doses, and preferably 

 intravenously. 



3. To be most effective the treatment should be given as early as 

 possible. 



The investigators in the Rockefeller Institute have divided the 

 pneumococci causing lobar pneumonia into four' main groups, and have 

 worked out a method for the rapid identification and classification of the 

 particular pneumococcus that is the etiologic factor in a given infection, 

 so that with the proper administration of the corresponding immune 

 serum very encouraging results have been obtained in the serum treat- 

 ment of pneumonia. These researches are of importance not only in 

 this connection, but also from the fact that they may have disclosed the 

 reasons for failure in the treatment of streptococcus and other infec- 

 tions, and that similar studies in these conditions may insure for serum 

 therapy a definite and valuable role in the treatment of disease. 



The Nature of Lobar Pneumonia. The frequency with which the 

 Diplococcus pneumonice is found in the local lesion and in severe cases in 

 the blood-stream of pneumonia patients, and the more recent experi- 

 mental studies of Wadsworth, 1 Meltzer, 2 Wollstein and Meltzer, 3 Win- 

 ternitz, Kline and Hirschfelder, 4 leave little doubt regarding the etio- 

 logic relationship of this microorganism to lobar pneumonia. Much still 

 remains to be learned, however, regarding the method of infection and 

 the nature of the resulting disease. While pneumococci are to be found 

 living in the upper air-passages as harmless parasites, it is probable that 

 those causing infection differ inherently as regards adaptation or viru- 

 lence for man. In addition, it is likely that general resistance is low- 

 ered in some more or less peculiar manner, and experimental studies 

 in animals, as well as the course of the disease in man, suggest most 

 strongly that local changes in the respiratory tract may precede the 

 infection, so that a combination of factors, such as the virulence of the 

 organisms and the diminished general and local resistance, plays a part 

 in the production of lobar pneumonia. 



In whatever manner produced, the disease is finally to be regarded 

 as a general infection, with localization of the process in the lung. While 

 pneumococci may be found in the blood of the most severe cases, the 

 general symptoms are apparently due to intoxication with a poison or 

 toxin derived primarily from the pneumococci, and secondarily from the 



1 Amer. Jour. Med. Sci., 1904, cxxvii, 851. 2 Jour. Exper. Med., 1912, xv, 133. 



3 Jour. Exper. Med., 1913, xvii, 353, RWR; ibid., 1913, xviii, 548. 



4 Jour. Exper. Med., 1912, xvii, 657; ibid., 1913, xviii, 50. 



