lOO LOCAL TLSSUE REACTlVriY 



pablc ol complete ncutiali/alion of as many as (jo leactiii!,; units 

 {i.e., no reactions ^vere oljseived in ral)l)its tested) . In sue h in- 

 stances the neutralizing titer of the sera could be accmately 

 derived by determining the largest amount of reacting factors 

 completely neutralized by a given serum. In other instances, only 

 irregular neutralizations coiUd be obtained even when small 

 amoinits of reacting factors were used. A large group of heter- 

 ologous rabbit and horse immune sera \vas also tested for neu- 

 tralizing potency of meningococcus reacting factors. Occasionally 

 heterologous or normal sera possessed a doubtful neutralizing 

 potency giving irregular neutralization of a small number of 

 reacting luiits. It thus became apparent that meningococcus react- 

 ing factors can be consistently neutralized. The antibodies, how- 

 ever, appeared only following special methods of immunization 

 and did not occur regularly in antimeningococcus immune sera 

 employed therapeutically. The matter ^vill receive special consid- 

 eration on the chapter concerning the therapeutic studies on the 

 neutralizing antibodies. 



In carrying out neutralization of B. coli reacting factors a dose 

 of 0.5 c.c. of the immmie serum gave more reliable results than 

 0.25 c.c. (an amoimt used for titration of neutralizing potency of 

 antityphoid serum) . This fact led to the observation on the so- 

 called auxiliary antibodies to be described subsecpiently in this 

 chapter. 



The titrations were carried out Avith niunerous batches of 

 anticoli horse sera. Several months of immunization yielded sera 

 capable of neutralizing in a dose of 0.5 c.c, frequently as many 

 as 75 to 100 reacting" units. Among various normal sera tested 

 only one batch was encoinitered which gave neutralization of 

 B. coli reacting units, the remaining control sera showing ir- 

 regular neutralization of reacting factors of B. dysenteriae, B. 

 pertussis and B. iiifiiuntzae, and, therefore, no statement can be 

 made as to the average potency of these sera. Satisfactory e\idence 

 ^vas obtained, however, that these reacting factors can be specifi- 

 cally and consistently neutralized by immune sera. 



The observations on the neutralizations of active principles of 

 the phenomenon by means of immune sera ^vere corroborated by 

 H. Gross (19310, b, c) , Mishulow\ Mowry and Scott (1930) , Sickles 

 (1931 and 1934, 1933, 1935) ^ Powell and jamieson (1931) , Plant 

 (1934), Pabst and Branham (1933), Linton, Singh and Seal 



