1^4 LOCAL ILSSUK REACIIVITY 



alcly and allci \aiiou.s periods ol time lollouiuo the intravenous 

 injection. 



Thus, the (question ol the late ol the active princ i|)les of the 

 j)henonienon in the blood stream remains open. Ihe neutraliza- 

 tion ol the leac ting factors by the natural antibodies of the animal 

 injected may be safely excluded, inasnuich as meningococcus re- 

 acting factors for whicii only insignificant amount of antibodies 

 is lound normallv, disappear from the blood stream just as 

 piom]nly as the B. lyl)hosus active principles. Another jjossible 

 explanation is that the active principles may be inactivated by 

 dilution in large amoinits of whole blood. This is, however, ex- 

 cluded by exj)eriments in which the potency of active meningo- 

 coccus and B. Ixphosus "agar washings" liltrates was retained when 

 mixed in \arious pioportioirs with whole dehbiinated rabbit's 

 blood. j)lasma and serum, and stored in the refrigerator for various 

 lengths of time; in some experiments as long as two to three 

 months. 



Work on the relation of the reticuloendothelial system to the 

 process of elimination of active principles from the blocxl stream 

 suggests itself. 



RECAPITULATION 



There is afforded uncjuestionable proof that there exists no re- 

 lationship whatscjever between the inflammation which may fol- 

 low' the intradermal injection of the preparatory factors and the 

 lesion characteristic of the phenomenon of local skin reactivity. 

 This is supported by observations in the gross, extensive histo- 

 logical studies, and by the fact that a large number of non-bacterial 

 substances iDringing about inflammation and injuries of various 

 types are incapable of eliciting the state of reactivity under dis- 

 cussion. Microscopically and in the gross, this phenomenon can be 

 clearly differentiated from the Arthus phenomenon. 



The essential prerecpiisite of the phenomenon of local skin 

 reactivity is that the provocative factors promptly enter into the 

 blood stream. The phenomenon is best elicited when the provoca- 

 tive injections are given intravenously and intracranially. Intra- 

 peritoneal injections elicit reactions in a certain percentage of 

 animals whilst the subcutaneous, intramuscular and oral admin- 

 istration of the active principles consistently fail to jiroduce re- 

 actions in the prepared skin sites. Histological studies further 

 substantiated the observation that repeated injections of active 



