122 LOCAL TISSUE REACTIVITY 



of xarioiis ainoimls ol anti-mcnin^occxx us Sciuin II7 liLxi- and 

 ot mixtures ot this serum ^vith diluted and undiluted anti-coli 

 liorse serimi H^o Bliss. Various amounts ot anti-meningococcus 

 serinn alone gave irregtdar neutralizations except when tested 

 with small niunbers of toxic imits. The addition of 0.1 c.c. of 

 the anti-coli serum previously diluted 1:^5 had no effect on neu- 

 tralizing potency. Mixttnes of amoimts as small as o.'^ c.c. and 0.6 

 c.c. of anti-meningococcus serum \vith 0.1 c.c. of undiluted anti- 

 coli serum did not result in any noticeable increase of the CN 

 titer. In spite of the fact that the latter amotnit of the anti-coli 

 serum coidd neutralize completely about 15 toxic tmits and 0.3 

 c.c. and o.fi c.c. of anti-meningococctis serum coidd neutralize com- 

 pletely 10 and 15 units, respectively, the mixture of 0.3 c.c. of 

 anti-meningococcus serimi ^vith 0.1 c.c. of undiluted anti-coli 

 serum neutralized completely less than 8 units, and the mixtine 

 of 0.6 c.c. of anti-meningococcus serum Avith the above amount of 

 anti-coli serinn neutralized completely only 15 imits, i.e., the same 

 nimiber of luiits xvhich could be neutralized independently by 

 either ingredient of the mixtine. Howe\er, \vhen 0.1 c.c. of lui- 

 diluted anti-coli serum was added to 0.9 c.c. of anti-meningococcus 

 serum, the mixtine ga\e complete neutralization cjf 35 toxic units, 

 although this amount of anti-meningococcus serum gave inde- 

 pendently only irregular neutralization of 20 units. 



From the foregoing observations it is seen again that the anti- 

 coli serum does not exhibit its independent neutralizing potency 

 '^vhen mixed ^v^ith anti-meningococcus serum containing neutraliz- 

 ing antibodies of low concentration (0.3 c.c. of H7 Blooo) ; that it 

 produces no effect when added to a some^vhat larger amount of 

 anti-meningococcus antibodies {i.e., 0.6 c.c. of H7 BI202) ; and that 

 it converts (beyond its o^vn neutralizing potency) irregular neu- 

 tralization into complete neutralization ^vhen added to a suflfi- 

 cient concentration of anti-meningococcus antibodies capable of 

 irregular neutralization. For these reasons it may be assumed that 

 the anti-coli serum contributes some auxiliary factor to the spe- 

 cific antibody-)-antigen combination and enters with it into an 

 intricate relationship. 



Further studies ^vere made in order to define closer the nature 

 of the auxiliary factor in the anti-coli horse sera. 



The anti-coli horse sera containing the auxiliary factor were 

 totally devoid of complement. There Avas no apparent relation 

 to the anti-complementary property of the sera because the same 



