HOST RESPONSE TO ANTIGENIC ACTION 475 



tures : local reactivity ; the short incubation period necessary to 

 induce the local reactivity ; the short duration of the state of reac- 

 tivity ; the ability to induce local reactivity by a single skin injec- 

 tion ; the severity of the reaction ; and the necessity of giving the 

 second injection of the toxic agent by the intravenous route. 



The phenomenon elicited by the injection of pneumococcal ma- 

 terials was first reported by Cope and Howell 277 in 1931. A sub- 

 stance obtained by dissolving pneumococci in bile evoked a local 

 skin reaction when its intradermal injection was followed by a sub- 

 sequent intravenous injection into rabbits. The reaction could not 

 be obtained by the use of pneumococcal filtrates prepared by meth- 

 ods in which the cell body was not disintegrated. Type-specificity 

 of the reaction was demonstrated in 44.4 per cent of the experi- 

 ments, but positive reactions were observed in 13.8 per cent of the 

 experiments in which heterogeneous types of pneumococci were 

 employed for the intradermal and intravenous injections. 



A wide deviation from type-specificity and even from species- 

 specificity in the mechanism of the phenomenon was later shown 

 by Shwartzman. 1264 Culture filtrates of Type III Pneumococcus 

 and agar washings of B. typhosus were simultaneously injected at 

 separate sites into the skin of the ear of rabbits. No reaction fol- 

 lowed this preparatory injection. When the pneumococcal filtrates 

 were injected intravenously twenty-four hours later, no activation 

 at the site of the pneumococcal extract injection occurred, but in 

 the majority of the animals a marked reaction was observed at the 

 point where the preparatory injection of washings of the typhoid 

 bacilli had been made. From the experiments, Shwartzman con- 

 cluded that pneumococcal filtrates were devoid of the preparatory 

 principle but were potent in reactive factors for B. typhosus agar- 

 washings if not for the pneumococcal substance. There was an- 

 other factor in the phenomenon, as observed under the experimen- 

 tal conditions, and that was the ability of pneumococcal extracts, 

 that had lost their reactivating power for preparatory injections 



