HOST RESPONSE TO ANTIGENIC ACTION 439 



* 



before crisis. While phagocytic and agglutinative activity were 

 observed for all the pneumococcal types tested, the reaction was 

 always strictly limited to organisms homologous with those with 

 which the patient was infected. 



Miiller (1923) 939 was inclined to ascribe to humoral antibodies 

 only a minor part in recovery from pneumonia. His belief was 

 based on negative results in tests for bactericidal power of serum 

 from the majority of patients studied, and also on the fact that 

 the author failed to observe any increase in the property during 

 the course of the disease. Adler (1923), 3 on the contrary, reported 

 that the serum of pneumonia patients developed the highest con- 

 tent of bacteriotropic substances at the time of crisis. However, 

 Baldwin and Rhoades (1925) 68 contended that recovery in pneu- 

 monia is associated with the appearance of specific antibodies in 

 the blood, and that the antagonistic action of the protective sub- 

 stance is revealed by the fact that pneumococci and protective an- 

 tibody rarely appear simultaneously in the circulating blood. The 

 presence of protective substance in the blood practically always 

 precluded a concurrent bacteriemia, but it did not in every case 

 prevent toxemia, relapse, or the development of complications. 

 Nevertheless, protective activity of the patient's serum appeared 

 to be an important factor in overcoming pneumococcal infection. 



With refined technique for determining the antagonistic action 

 of serum from pneumonia patients, Sia, Robertson, Woo, and 

 Cheer (1925) 1274 found that in all cases of pneumonia studied the 

 serum at or soon after crisis possessed the power to inhibit growth 

 of pneumococci in rabbit serum-leucocyte mixtures. Before crisis, 

 serum either lacked the property or exhibited it only to a slight 

 degree. The titer reached its highest point three or four days fol- 

 lowing crisis and then gradually diminished, although in one pa- 

 tient recovering spontaneously from pneumonia due to Type I 

 Pneumococcus antipneumococcic substances were still demonstra- 

 ble in the blood for seventy days. In cases terminating fatally no 



