i8 



I.OCAI. TISSUE REACTIVITY 



simultaneous injections ol xarious dilutions oi meningococcus 

 "agar washings" filtiates iiUo liie (iciniis ol the i)ack. These dilu- 

 tions Aveie 1:100, 1 :()()(), 1:1000, and 1:1 ]oo. l'\)ll()\ving the in- 



TiG. (). skill ol liack of rabbit iccci\etl eight intiatlennal injections ot nieningococcus 

 active principles in cliliitions ranging trom 1:2 to 1:300. Twenty-four fiours later, 100 

 tmits of meningococcus acti\e principles were injected intravenously. Note severe 

 hemorrhagic reactions at prepared sites. 



travenous injection ot an appropriate dose, reactions were ob- 

 tained in areas prepared with dilutions of filtrate 1:400, 1:600, 

 and 1:1000 and no reactions in the sites prepared with the dilu- 

 tion 1:1400. In another group of six rabbits, the sites of the back 

 \vere prepared with dilutions 1:600, 1:800, 1:1000, and 1:1200. 

 Follo^ving" the intravenous injection of the same dose as employed 

 in the previous experiment, no reactions appeared in the prepared 

 skin sites. 



Thus, the paradoxical observation Avas made that sites prepared 



