REACTING POTENCY 259 



supernatant fluid ^vas clear. The supernatant fliiicl was removed 

 and the sediment suspended in a \olinne of 0.85 per cent NaCl 

 soltition equal to one-fourth of the \'okmie of tlie antibody- 

 containing serinn. Rabbits recei\ed a single intradermal injection 

 of 0.25 c.c. of inidiluted B. tyjjliosiis "agar ^vashings" filtrate or 

 meningococcus Group III, 44B. "agar washings" filtrate, diluted 

 1:2 and twenty-fotu' hoins later an intra^'enous injection of the 

 material tested. There 'were no deaths iollo\ving these injections. 

 The lesions obtained in ])repared skin sites ^vere very intense in 

 the majority of positive rabbits and were characteristic of the 

 phenomenon of local skin reactivity to bacterial filtrates as seen 

 from gross and histologic studies. 



The follo^ving coml)inations proved successftd: 



1. Human serum \vith anti-htmian horse senmi; 2. Horse serimi 

 ^vith rabbit anti-horse serimi; 3. Himian sertmi ^vith rabbit anti- 

 himian serimi; 4. Sheep serum ^vith rabbit anti-sheep serum; 5. 

 Horse serum with anti-horse goat serimr; 6. Egg albumin ^vith 

 anti-rabbit egg albimiin serimi. 



W^itli doses of 1 to 2 c.c. per kilo of body ^veight of the fore- 

 going combinations 1 to 4, there ^vere obtained 85 per cent 

 positive results. The data concerning the incidence of reactions 

 with combinations 5 and 6 are too meagre to allow estimation of 

 incidence of reactions (Shwartzman, 1931^, 1932^-'). 



The reacting potency of some of the abo\e combinations ^vas 

 corroborated by Plant (1934) , P. Bordet (1936/-') , Wadsworth and 

 Sickles (1933) , and others. 



REACTING POTENCY OF COMPLEXES OF RABBIT SERUM WITH 

 ANTI-RABBIT HORSE AND GUINEA PIG SERA 



Combinations of anti-rabbit horse serum undiluted and rab- 

 bit serum in various dilutions 'were tested. Positive results ^vere 

 obtained ^vitli rabbit serum diluted 1:80 and 1:120 in one-third 

 of the rabbits and negative results with other dilutions. Of some- 

 ^vhat more regular incidence Avere reactions obtained ^vith com- 

 binations of rabbit serum Avith one batch of anti-rabbit guinea 

 pig serum (1:50, i;ioo, and 1:200 dilutions of rabbit serum). 

 Another batch of anti-rabliit guinea pig serum ga\e jjositive 

 results ^vlien injected by itself. It is possil^le than an in vii>o 

 interaction occurred between the serum injected and the rabbit's 

 blood. This phase of the work inxohes the question of reacting 



