REACTING POTENCY 281 



nous injection, Avhilst others l:)ecame refractory after one or sev- 

 eral reactions. 



It is possible, then, to elicit the phenomenon of local skin re- 

 acti\ity to bacterial liltrates by repeated weekly intravenous 

 injections of tuberculous materials into rabljits prepared by 

 intradermal injections of bacterial filtrates of ascertained skin- 

 preparatory potency (meningococcus, B. typhosus, etc.) (Sh^vartz- 

 man, 1935/;) . 



Some bacterial antigens failed thus far to elicit the phenom- 

 enon in spite of Aveekly retests, namely. Streptococcus iiiridnus, 

 and B. meliteusis. 



FORMATION OF REACTING FACTORS IN RABBITS PASSIVELY SENSITIZED 

 TO BACTERIAL FILTRATES 



B. tuberculosis: 



The tuberculous antisera employed for passive transfer were 

 sera of rabbits showing reactions in the foregoing experiments on 

 acti\e sensitization to tuberculous materials, sera of human cases 

 of tuberculosis and tuberculous guinea pigs. With a possible excep- 

 tion of one instance, all the experiments failed. 



Pneumccoccus Type III : 



In contradistinction to experiments with B. tuberculosis, pas- 

 sively acquired pneumococcus antigen -[-antibody complexes Avere 

 capable of eliciting reactions in the prepared skin sites. In these 

 experiments, twenty-three and one-half hoins after the skin prep- 

 aration with bacterial filtrates, 3 c.c. of pneumococcus Type III 

 culture filtrate (incapable of eliciting the phenomenon by itself) 

 were injected intravenously and one-half hour later, 1 c.c. of anti- 

 pneumococcus Type III horse serum was also injected intra- 

 \enously. Severe reactions appeared in most of the rabbits thus 

 treated (Shwartzman, 1932/). 



FORMATION OF REACTING FACTORS THROUGH INTERACTION OF ANTI- 

 GEN OR ANTIBODY INJECTED INTO THE PREPARED SITE WITH 

 ANTIBODY OR ANTIGEN INJECTED INTRAVENOUSLY 



From the foregoing it appears that an intra\ascular interaction 

 between antigen and antibody is essential for elicitation of hemor- 

 rhagic necrosis in prepared skin sites. It was deemed of interest 

 to determine whether the reaction could also take place if either 

 the antigen or the antibodv was present in the blood stream at 



