SIGNIFICANCE OF PHENOMENON 363 



is induced at the site ot the localization of the acti\e principles, 

 the antigen interacting ^vith the circidating anti-bacterial anti- 

 bodies may then produce a local hemorrhagic and necrotic re- 

 action in the site of the tid)erculin test. This is indeed well sup- 

 ported by the fact that in contradistinction to anaphylaxis, skin 

 reactions of bacterial allergy reqtiire a number of hoins for their 

 appearance. The delay, may be due to the fact that the localized 

 active principles must induce a state of reactivity in the tissue 

 before a reaction can take place. 



The hetero-allergic skin reactions of tidjercidous patients and 

 animals, i.e., enhanced reactions to cutaneous injection of heter- 

 ologous bacterial prodticts and \'arious other irritants may be 

 similarly explained. Here again the active principles secreted by 

 tuberctdous foci may localize from the blood stream in sites 

 inflamed through the injection of irritants. The active principles 

 thus localized may elicit the state of reactivity. The reacti\'e sites 

 may then, in tinn, inidergo severe injiny when reacting" factors 

 are introdticed into the blood stream. These reacting factors may 

 either be dcrixed from bacteria or restilt from interaction be- 

 t^veen antigens with antibodies. The antigens in these complexes 

 may be animal proteins and bear no relationship to the infecting 

 antigen. 



The scattered observations revie^ved above on the enhanced 

 lethal effect of heterologous filtrates upon infected animals are 

 brought into the realm of the phenomenon of local tissue reac- 

 tivity because of the incidental hemorrhagic lesions noted at sites 

 of infections (P. Bordet) . It is conceivable that these severe 

 lesions obtained may be by themselves responsible for the pro- 

 tracted shock and death, especially when occtuTing in internal 

 organs. An observation previously not recorded but frequently 

 made by me ^vas that rabbits receiving simtdtaneously several in- 

 tradermal injections may show a higher mortality rate upon the 

 intravenous injection of a bacterial filtrate than rabbits prepared 

 by single intradermal injection. Although without any definite 

 proof this observation suggests that sites, in ^vhich a reaction 

 occurs following the provocative injection of the active principles, 

 may release factors of lethal potency ^vhich reach a concentration 

 stifficient to kill the animal if such release occurs at several sites. 



Thus, in the light of the ofjservations made on the phenom- 

 enon of local tissue reactivity, bacterial allergy may present the 

 foUo^ving doidjle-phased mechanism. 



