28o LOCAL TLSSUE REACTIVITY 



also injected inlraNcnously into rabbits j)rc'|)arc(l l)y a single in- 

 tradermal injection ol the above B. Iyj/h().\ii.s liltrate twenty-four 

 hoins l)ef()re. The rabbits reinjected intradernially showed no 

 hemorrhagic necrosis dining the following forty-eight hours of 

 observation. The rabbits injected intravenously had severe hemor- 

 rhagic and necrotic lesions at the prepared skin sites lour to five 

 hoins later. 



Thus, the essential prerecjuisite was that the antigen-)-aiuibody 

 mixture be brougiit into contact ^vith the prepared skin areas 

 i)ia the blood stream. 



FORMATION OF RF.ACTING FACTORS IN RABBITS ACTIVELY SENSITIZED 

 TO BACTERIAL SUBSTANCES 



The experiments on the effect of intravenous interaction of 

 tuberculous materials with homologous antibodies upon skin sites 

 prepared by injection of potent bacterial filtrates were conducted 

 in a manner similar to those just described. 



Fifteen groups of 3 rabbits each ^vere given \veekly single intra- 

 dermal injections of bacterial filtrates of ascertained skin-prepara- 

 tory potency. Twenty-four hours after each intradermal injection 

 the rabbits ^vere injected intravenously with certain tuberculin 

 O. T. liatches and filtrates of tuberculous cultures of various ages. 



Following the first intravenous injection of the materials se- 

 lected, no reactions appeared in the prepared sites. After the 

 second injection there appeared reactions in Group I. The third 

 injection produced hemorrhagic necrosis again in Group I and 

 also in Groups II and III. As a result of the fourth injection, re- 

 actions were obtained in previously susceptible Group I and new 

 Ciroups IV and V. The fifth injection produced repeated reactions 

 in Ciroups I and V; the sixth injection, repeated reactions in 

 Groups I and V and in previously non-reactive Groups VI and 

 VII, and finally, the seventh injection elicited hemorrhagic nec- 

 rosis in new Groups VIII, IX, X, and XI, and the previously re- 

 active Group I. The reactions elicited in the manner described 

 were obtained witir tuberculin O. T. preparations of human, 

 bovine, and avian types and bovine, human and avian tuber- 

 culous culture filtrates of four and nine weeks' incubation and 

 failed with two five day and one eight week old culture filtrates 

 of bovine type. It is of interest that some of the groups once re- 

 active continued to show reactions Avith each subsequent intrave- 



