390 BIOLOGY OF PNEUMOCOCCUS 



and not on the leucocytes. Complement was not necessary to ren- 

 der the organisms phagocytable. In a second report, Neufeld and 

 Rimpau (1905) 998 claimed that the theory that serum was a stimu- 

 lant for the leucocytes was no longer tenable, but that serum, on 

 the contrary, caused a peculiar transformation of the bacteria. 

 Immune serums which possessed the property of rendering bac- 

 teria susceptible to phagocytosis Neufeld and Rimpau designated 

 by the name "bacteriotropic" to distinguish them from bacterio- 

 lytic serums. 



In America, at the time when the Wright opsonic technique was 

 arousing such general interest, Rosenow 1160 tested the suscepti- 

 bility of forty strains of pneumococci to phagocytosis. All but 

 four strains at first resisted phagocytosis in pneumonic blood, but 

 after cultivation on artificial media the organisms became suscep- 

 tible to leucocytic ingestion. While heating the cocci had no effect 

 on susceptibility, the opsonic property of the serum appeared to 

 be diminished after a thirty-minute exposure to a temperature of 

 56°. Rosenow believed that white cells from the blood of pneu- 

 monia patients possessed greater phagocytic power than did nor- 

 mal cells, and ascribed the pneumococcidal effect of blood to the 

 combined action of serum and leucocytes — phagocytosis and in- 

 traphagocytic digestion. Potter and Krumwiede (1907) 1103 tested 

 the leucocytes of pneumonia patients for phagocytic properties. 

 While granting the inaccuracy of the method employed, the au- 

 thors, contrary to Rosenow, stated that leucocytes of patients 

 during the height of pneumonic disease were probably less active 

 in phagocytic power than were normal leucocytes. 



The principle in leucocytes responsible for the lysis of pneumo- 

 cocci after being phagocyted was investigated by Schneider 

 (1910), 1244 who believed that the hypothetical substance acted 

 directly upon the injected pneumococci. Schneider also found that 

 specific immune serum powerfully stimulated phagocytosis, espe- 

 cially in vivo, but ascribed the action of serum to its effect on the 

 white cells. Schneider further claimed that a serum which was 



