APPLICATION OF THE PHENOMENON 40 1 



doses of killed cocci and 2 doses of the maxiniuiii of 20 c.c. of 

 meninoococcus '"aoar ^vashinos" filtrates had been administered 



O r> C) 



weekly on alternate days. The filtrates were injected subcutane- 

 oiisly and intramiiscidarly. Each animal received material repre- 

 senting" the 4 commonly knoAvn groups of meningococcus. These 

 authors also failed to correlate agglutinin contents of the sera 

 thus obtained with the anti-meningococcus neutralizing anti- 

 bodies. The added treatment with the active principles of men- 

 ingococcus sufficed in their hands to increase the potency of neu- 

 tralizing antibodies. It has also been noted by them that the 

 neutralizing potency of the sera did not parallel the agglutina- 

 tion titers. There seems to be. ho^vever, some parallelism bet^veen 

 the neiUralizing and motise protection potencies of the sera. 

 According to studies of Po^vell and Jamieson Avith 6 antisera, the 

 lethal effect of live cidtures of meningococcus ^vas blocked by the 

 sera containing neiUralizing antiljodies approximately to the same 

 extent as the phenomenon in rabbits. 



Sickles (i9;^3. ^9^Fi) studied the ability of anti-meningococcus 

 sera to neiUralize the skin-preparatory factors in the follo^sing 

 manner: 



Large chinchilla rabbits were depilated on the back and in- 

 jected intraciUaneously ^vith a series of mixtines of dihuions of 

 the active meningococcus filtrate and the serimi to be tested (in- 

 cubation for thirty miniUes at 37^ c.) . The same dilutions of fil- 

 trate mixed Avith normal horse seriuu Avere put on every rabbit 

 as a control. Eighteen hours after the intracutaneous dose the 

 rabbits received 0.2 per cent agar in 0.85 per cent salt soliuion. 

 Although "agar w'ashings" bacterial filtrates coidd also be used, 

 the agar in her hands had the advantage of not changing the titer 

 and not killing the rabbits. Readings "were made in foin^ to five 

 horns. Equal parts of filtrate dihuions and serimi dilutions were 

 injected intracutaneously in 0.4 c.c. amounts. The dose of agar 

 was usually 5 c.c. Titrations of bleedings from horses under im- 

 mimization Avith li\e cidtines and toxic filtrates ^vere all done by 

 this method. 



Serum obtained from one of these horses proved to ha\e a 

 higher neiUralizing potency than many of the routine sera ^vhen 

 tested iDy this method. Serum from another horse under im- 

 munization ^vith 6 strains of live cultures injected intraxenously 

 only was just as high. The serum of a second horse under 

 immunization by the same method and the same strains for the 



