SIGNIFICANCE OF PHENOMENON 371 



enon are excreted in the mine by severe cases ot typhoid fever 

 in amoiuits sufficient for elicitation of the phenomenon in rab- 

 bits. He considers the fact as an indication that the toxic sub- 

 stances of the phenomenon may play a significant role in the 

 toxic manifestations of typhoid fexer. 



NEUTRALIZING POTENCY OF SERA FROM MENINGOCOCCUS INFECTIONS 



The folloAving studies afford further support to the assumption 

 that the acti\e principles of the phenomenon may play an im- 

 portant role in spontaneous diseases. 



Powell and jamieson tested for neutralizing potency 3 samples 

 of serum from individuals recovering (one to three months after 

 onset of the disease) from severe meningococcus meningitis and 

 one sample from a clinician Avho daily treated several cases and 

 ^vho was for a time a carrier of meningococcus. 



The rabbits were prepared by intradermal injection of 0.25 c.c 

 of meningococcus "agar washings" filtrates diluted 1:2 and twenty- 

 four hours later injected intravenously with 1 c.c. of the filtrate 

 diluted 1:5 in mixture with various dilutions of the sera. Each 

 serum dilution was tested in a group of foiu' rabbits. The three 

 convalescent sera neutralized the meningococcus "agar ^vashings" 

 filtrates when diluted 1:5 btit did not do so when diluted 1:10. 

 The serum from the healthy carrier did not neutralize when di- 

 luted 1:5. 



In careftilly controlled experiments Klein (1933) was able to 

 find neutralizing potency in sera of 2 patients. The antibodies 

 seemed to be limited to the active principles of one serological 

 group of meningococctis. Thus, one j^atient (G. R.) gave con- 

 sistent neutralizations with S tmits of Group I active principles 

 and no neutralization Avith 8 units of actixe principles of Groups 

 II, III, and I\'. Serum "J. C." gave consistent netitralization with 

 10 units of Group III filtrate but none with 3 units of filtrate of 

 Groups I and II. "M. K." serum gave consistent neutralization 

 with 25 units of Group I filtrate but only irregular neutralization 

 or none with 3 units of Groups II. Ill, and IV. There seemed to 

 be no relationship between the presence of neutralizing potency 

 and the length of time elapsed from the date of meningococcus 

 infection to the date of bleeding in the sample of serum exam- 

 ined. Serum of "M. B." was titrated only two months after her 

 illness. No appreciable neutralizing potency was present (none 

 ^vith 3 units of filtrates of all 4 groups) . Serum of "H. K." was 



