292 LOCAL ILSSLE REACTIVITY 



doses of I). (;. (i. as small as 0.1 and 0.01 ol in^ni. ol moist \vci<;ht 

 arc more la\<)ral)le than 1 mi>in. T)j)ical reactions were obtained 

 ^vith fi\e, twenty lour, lorty-eight, and sexenty-two hoins' inter- 

 vals i^etween the B. C. (i. and test injections. No reactions were 

 obtained Avitli se\en and fourteen days' intervals. Under the l)est 

 conditions one-tiiird of the ral)ljits failed to react. The lesions 

 were similar in apj^earance to those elicited by means of the 

 provocative intravenous injection of liacterial active principles. 



RECAPITULATION 



Mixtures of certain animal and bacterial proteins with homol- 

 ogous antisera injected intravenously into rabbits prepared intra- 

 dermally xvith bacterial active principles of the phenomenon 

 elicit prompt hemorrhagic necrosis in the prepared sites. 



The reacting potency of the complexes may be imparted either 

 by the antigen or the antibody and represents a certain inherent 

 toxic quality Avhich is apparently liberated through the interac- 

 tion between the antigen with the antibody. It was shown that 

 the reacting potency does not depend either upon the amoinit 

 of precipitate obtained or on the size of the aggregate formed 

 i)i nitro. 



The antigen -[-antibody mixtures endowed xvith strong reacting 

 potency are completely devoid of preparatory potency. 



With the exception of agar and possi])ly starch, a great variety 

 of inert colloids are devoid of reacting })otency. WHiole blood 

 and blood sera of rabbit, dog, ox, chicken, horse, sheep, rat and 

 mouse also fail to produce reactions in skin sites prepared \vith 

 bacterial filtrates. Reactions may be irregularly obtained xvith 

 guinea })ig and human blood. This may be due to in vivo inter- 

 action betAveen the rabbit natural Forssman antibody and the 

 Forssman antigen of the blood of these animals. 



The interaction of antigens with antibodies occmring /// vivo 

 also elicits strong hemorrhagic and necrotic reactions in skin 

 sites prepared Avith bacterial active principles. It is essential that 

 the interaction occur in the blood stream. It may be obtained in 

 one of the following manners: 



By separate intra\enous injection of the antigen and the anti- 

 body; by intravenous injection of the antigen into an animal pos- 

 sessing actively acquired homologous antibodies; by injection of 

 the antigen into the site prepared with bacterial active principles 

 accompanied by a simultaneous intra\'enous injection of the anti- 



