420 BIOLOGY OF PNEUMOCOCCUS 



protective action of specific antipneumococcic serum. These fac- 

 tors, described by Felton 405 for the mouse, and by Goodner, 532 " 4 

 and Goodner and Miller 540 for the mouse and rabbit, have already 

 been mentioned in the chapter on antigenicity and need not be 

 repeated. 



For elimination of the variables in the animal host, for sim- 

 plicity and rapidity of performance, the newer methods based on 

 specific precipitation present many advantages over the mouse 

 protection test for the quantitative determination of protective 

 antibody in antipneumococcic serum. 



Other Immunological Phenomena 



GROWTH OF PNEUMOCOCCI IN SPECIFIC IMMUNE SERUM 



The growth of pneumococci in immune serum was observed by 

 Metchnikoff 894 in 1891, and Denys (1897) 312 reported that pneu- 

 mococci grow as well in immune as in normal rabbit serum. In the 

 experiments of Rosenow (1904), 1159 pneumonic blood was found to 

 possess no bactericidal properties for Pneumococcus, while viable 

 organisms could be propagated from agglutinated masses of the 

 cocci in the serum of pneumonia patients. An initial lag in the mul- 

 tiplication of pneumococci planted in the serum of artificially im- 

 munized animals, followed by active proliferation of the cells, was 

 described in 1920 by Bull and Bartual. 177 Nicolle and Cesari 

 (1926) 1008 obtained better growth in Martin bouillon containing 

 specific homologous serum than in the same medium to which het- 

 erologous immune or normal serum had been added. The ability of 

 pneumococci to grow in homologous anti-S and anti-R immune se- 

 rum and the effects of the serum on the growth of the cocci has 

 been described in Chapter V. 



ANTIBLASTIC IMMUNITY 



An action of antipneumococcic serum apparently not definitely 

 attributable to any of the known specific antibodies was described 



