284 I.OCAI. TISSUE REACTIVITY 



tlie bacterial filtrate is made into the tissues (j)eri\as( ular prep- 

 aration) , whilst the provocative injection is made intravascularly. 

 However, the bacterial filtrates can also elicit the necessary pre- 

 paratory effect by ^vay of the vascular system j^rcjvided the lo- 

 calization ol the preparatory factors from the blood stream is 

 brought about through the use of some accompanying agent 

 (heat, Reynal's testicular extract) . It remained, then, to deter- 

 mine whether an intravascular interaction of locally injected 

 animal protein antigen ^vith actively accjuired antibodies is ca- 

 pable of eliciting the state of reactivity t(j bacterial filtrates and 

 also to determine whether bacterial filtrates injected intravascu- 

 larly are capable of eliciting a local state of reactixity to anti- 

 gen-[-antibody complexes interacting intravascidarly. 



Rabbits received one sensitizing intravenous injection of nor- 

 mal horse serum in a dose of 1 c.c. per kilo of body xveight. 

 Intradermal tests "vvith horse serum Avere made six days after 

 the intraxenous sensitizing injection. Rabbits thus sensitized and 

 otherwise untreated, gave no significant reactions outside of slight 

 erythema and occasional edema. As is xvell knoxvn, the Arthus 

 phenomenon requires repeated sensitizations over a period of 

 several weeks. Five-tenths c.c. was used for the test injections. 

 Preliminary experiments showed that doses smaller than 0.5 c.c. 

 gave inconsistent results. The above treatment xvas combined 

 with injections of bacterial filtrates. The positive reactions, about 

 to be described, were hemorrhagic and necrotic lesions typical 

 of the phenomenon of local skin reactivity to bacterial filtrates. 

 They w-ere considered prompt xvhen they appeared three to 

 five hours after the test injection xvith horse serum and delayed 

 Avhen they developed twenty-four hoins later. 



Sensitized rabbits receiving intravenous injections of loacterial 

 filtrates simultaneously with the intradermal test xvith horse 

 serum and one hour following it, showed no prompt local reac- 

 tions. In one rabbit the intravenous injection of 75 units of men- 

 ingococcus fdtrate given one hour after the intradermal test xvith 

 horse serum, gave a delayed reaction. When the intravenous in- 

 jection of bacterial filtrates xvas gixen six, eighteen, and txventy- 

 four lioms folloxving the intradermal injection of horse serum, 

 hemorrhagic reactions appeared in the sites tested. No reactions 

 were obtained xvhen the interval of time betxveen the intravenous 

 injection of bacterial filtrate and the intradermal test xvith horse 



