474 BIOLOGY OF PNEUMOCOCCUS 



sequent reactivity of the dermal cells, and this fact is to be borne 

 in mind in studies on skin sensitivity where repeated intradermal 

 injections of these agents are involved. 



The true nature of the phenomenon of skin reactivity to Pneu- 

 mococcus or its components still remains hidden. The resulting 

 skin activity to capsular polysaccharide following the administra- 

 tion of homologous type-specific antipneumococcic serum has led 

 to the hypothesis that the specific reaction is to be explained on 

 the basis of local interaction of antigen and circulating antibody 

 in the dermal tissues but the hypothesis fails to account for the re- 

 peated observation that a negative cutaneous reaction may be ob- 

 tained even when the blood of the subject contains demonstrable 

 antibodies. There is, to be sure, a certain parallelism between the 

 results of serological tests and skin tests in pneumococcal pneu- 

 monia with the somatic carbohydrate C, but the correlation does 

 not necessarily hold when the capsular polysaccharide is used as 

 the test material. 



The claim that pneumococcal toxins and their homologous anti- 

 toxins operate in this immunological reaction requires further 

 investigation before it can be accepted. The participation of hu- 

 moral antibody and the possible reactivity of the dermal cells 

 induced by pneumococcal infections are questions shrouded in ob- 

 scurity, and it would be presumptuous at the present time to ven- 

 ture any more definite statements regarding this interesting and 

 important phenomenon. 



THE SHWARTZMAN PHENOMENON 



In 1928, Shwartzman 1263 described a dermal reaction to bacterial 

 extracts in rabbits, which consisted in a severe local activation, by 

 intravenous injection of the extract, of a previously inert intra- 

 dermal injection of the same material. The phenomenon — since 

 called the Shwartzman phenomenon — appeared to differ from the 

 usual toxic or allergic cutaneous reactions in the following fea- 



