ANTIBODIES TO PNEUMOCOCCUS 395 



showed a similar early diminution of humoral immune substances, 

 but with the onset of recovery the concentration of the immune 

 bodies again rose. When the infection was localized, as in the case 

 of true lobar pneumonia, the presence of humoral antibodies in 

 quantity could be demonstrated in the blood throughout the course 

 of an infection terminating in death. 



Other evidence indicating the participation of leucocytosis in 

 resistance to pneumococcal infections is to be found in the com- 

 munication of Schattenberg and Harris (1932). 1222 The plan of 

 the experiments was to induce leucocytosis in white mice by pre- 

 liminary injections of killed cultures of typhoid bacilli or staphy- 

 lococci, of detoxified suspensions of devitalized pneumococci, and 

 of sterile milk. Six to eight hours later the animals were inocu- 

 lated intraperitoneally with lethal doses of pneumococci of Types 

 I, II, and III so measured that death of the mice could be con- 

 trolled to take place at periods varying from three to twenty-four 

 hours. The animals thus treated failed to show that stimulation of 

 leucocytosis had any effect in preventing the development of pneu- 

 mococcal peritonitis. 



NORMAL TROPINS OR OPSONINS 



The ability so to sensitize pneumococci that they become attrac- 

 tive to leucocytes and susceptible to phagocytic lysis is a charac- 

 ter of some normal as well as of immune serums. Rosenow 1160 " 1 dis- 

 closed the property in normal human serum and found opsonins 

 for streptococci, staphylococci, and tubercle bacilli, in addition to 

 those for pneumococci. 



Ungermann (1911) 1434 was unable to discover any phagocytosis 

 of virulent pneumococci in the serum of normal mice and rabbits. 

 Avirulent strains were readily phagocyted, and the degree of the 

 action appeared to parallel the resistance of the particular species 

 of animal whose serum was used. The conclusion was reached that 

 normal resistance depended upon the phagocytic power of fresh 

 normal serum, at least in the cases studied, and that the serum must 



