286 LOCAL TLSSLE REACTIVITY 



sensiti/aLioii was six days. Bacterial filtrates were injected in- 

 travenously preceding the skin test at time intervals ranging horn 

 one to ninety-six hours. Active and inactive bacterial filtrates 

 ^vere employed. Among the active ones there were those of both 

 high skin-preparatory and provocative potency (B. typhosus l\\- 

 trates) ; those of high skin-preparatory potency and lesser pro- 

 vocative potency (tneitingococcus and B. enteritidis filtrates) ; 

 and those ^vith moderate provocative potency but inactive as 

 skin-preparatory factors [Streptococcus hemolyticus and B. tu- 

 berculosis filtrates) . The titration of the phenomenon-producing 

 potency of the varic^us bacterial filtrates is presented in Table IX. 



When the intravenous injection of B. typhosus "agar wash- 

 ings" filtrates (5 to 25 units) preceded by one hour the intrader- 

 mal test with horse seriun in rab])its sensitized to horse serum, 

 there developed severe but delayed local reactions. No reactions 

 were obtained in sites with horse serum tests if preceded six 

 hours before by the intravenous injection of B. typhosus "agar 

 washings" filtrates, in a dose of 25 imits. W^hen the B. typhosus 

 filtrate was injected eighteen and twenty-four hours prior to the 

 test, there appeared delayed and also some prompt reactions. 

 W'itii longer intervals of time bet^veen the injection of B. ty- 

 pJiosus filtrate and the intradermal test with horse serum, no 

 reactions appeared (forty-eight and ninety-six hours) . W^hen the 

 intravenous injection of meningococcus "agar washings" filtrates 

 preceded by one hour the intradermal test \\'nh hearse serimi in 

 rabbits sensitized ^vith horse seriuu, it ^vas recjuired to use at 

 least 75 reacting imits in order to produce reactions. No reac- 

 tions appeared in the intradermal sites of tests with horse serum, 

 with intravenous injections of 25 units of B. oiteritidis and 2 

 c.c. per kilo of body ^veight, of human tid^erculosis culttue fil- 

 trate and Streptococcus Jieruolyticus filtrate. 



As may be seen from the data thus far presented, filtrates en- 

 dowed ^vith reacting poteircy but devoid of skin-preparatc:)ry fac- 

 tors failed to elicit the reactions. When B. enteritidis filtrates 

 possessing both skin-preparatory and reacting potency were em- 

 ployed the dilutions representing 15 skin-preparatory doses also 

 failed to elicit the reactions in spite of the fact that they con- 

 tained as many as 25 reacting units. Convincing results, ho^vever, 

 were afforded by comparison of the effect of B. typhosus and 

 meningcjcoccus filtrates. As is seen from Table ix, the skin-pre- 



