54 LOCAL TLSSIIE REACTIVITY 



ile filter j)apci. The liltiates were translerred to sterile be.ikers 

 and evaporated to i lo original Nolmiie in the water bath at 

 56° c. The length of time re(jiiired lor evaporation varied ironi 

 twenty-foin- to thirty-six hoius. 



In preliminary experiments, the primary irritating effect ot 

 intradermal injections of tiU)erciilin C). T., and various (idtme 

 filtrates \vas stndied. Filtrates gave no local reactions. Lhidihited 

 tuberculin frecjiiently produced pnstides with hemorrhagic zones 

 at the peri])hery twenty-four hours after intradermal injections. 

 Dilutions 1:^^ elicited small pustides with a bright red erythema 

 at the periphery. Dilutions 1:5 and higher gave no noticeable in- 

 flammatory response. The irritation described was apparently due 

 to the high concentration of glycerine, since preparations of 25 

 and 50 per cent glycerine in plain sterile broth gave similar re- 

 actions. In the experiments which follo^v, it seemed advisable to 

 avoid primary skin irritation, since it w^as previously observed 

 that in instances in which the preparatory factors produced no 

 primary reaction, the lesions following intravenous injections of 

 bacterial filtrates were clearly defined and stronger than when the 

 intradermal injections by themselves elicited inflammation. 



An undiluted filtrate and several batches of tubercidin O. T., 

 diluted 1:7.5 were employed for preparation of the skin. Twenty- 

 foiu" hoiu's later, large doses of B. tuberculosis filtrates and tuber- 

 cidin ^vere injected intravenously. No reactions 'were seen four 

 and t\venty-foin' hoins after the intra\enous injection. 



In another series of experiments the skin of rabbits was pre- 

 pared by single injections of 0.25 c.c. of various batches of luunan 

 and bovine tuberculin O. T., a filtrate of bovine B. tuberculosis 

 broth culture and purified tuberculin T. P. T. (kindly supplied 

 by Dr. Florence Seibert) . T^venty-foiu' hours later, the rabbits re- 

 ceived single intravenous injections of potent meningococcus and 

 B. typhosus "agar Avashings" filtrates. 



In these experiments, batches of human and bovine tuberculin 

 O. T., prepared in my laboratories, were capable of inducing the 

 state of reactivity. Similar attempts with the Ne^v York Board of 

 Health tid^ercidins and ^vith the piuified T. P. T. tid)erculin con- 

 sistently failed. It became ob\'ious then that the skin-preparatory 

 factors are foiuid in tul:)ercidins in low and variable concentra- 

 tions. 



In the third series of experiments, meningococcus and B. ty- 



