SIGNIFICANCE OF PHENOMENON 387 



the infection and its state of reactivity. For unknown reasons vac- 

 cinia virus infections are most susceptible to the intravenous in- 

 jection of reacting- factors on the third and sixth day (Gratia and 

 Linz, and KopHk) . The tuberculous lesion may best react on the 

 fomth and eighth day following the intradermal inociUation of 

 B. tuberculosis. The state of reactivity of an infected tissue is not 

 continuous. It disappears and reappears at some later stage. This 

 variability may be responsible for the fact that the hemorrhagic 

 manifestations of spontaneous diseases do not present a constant 

 syndrome. 



EFFECT OF THE PHENOMENON OF LOCAL TISSUE REACTIVITY UPON 

 EVOLUTION OF LOCAL INFECTIONS 



The hemorrhagic reaction of the phenomenon occurring in 

 infected sites may favorably influence the cotuse of the infection. 

 Thus, it ^vas shown by Gratia and Linz that vaccinia in B. 

 fuifJnacis infections ordinarily fatal to rabbits may result in com- 

 plete healing after the reaction occurs at these sites. As already 

 mentioned, Apitz reported that previous treatment of rabbits Avith 

 small doses of B. coli active principles may favorably influence 

 the course of infection produced by intravenous injection of live 

 staphylococctis. P. Bordet infected rabbits by sidDcutaneotis in- 

 jections of live cultures of B. coli and B. paratyl)Jiosus B. and then 

 injected intravenously active B. coli filtrates. Some of the rabbits 

 developed typical hemorrhagic reactions at the infected sites fol- 

 lo\ving the intraxenotis injection of the filtrate. The e\olution of 

 the lesion appeared favorably modified in extent and degree of 

 inflammation. Michelazzi (1936) found that rabbits previously 

 treated with B. coli culture filtrates showed a decided increase 

 in resistance to subcutaneous infection with live tubercle bacilli. 

 On the contrary, when the tubercle bacilli were injected intra- 

 venously into B. coli treated animals, the ttiberctilotis lesions were 

 more extensive than in control animals. 



It is difficult to interpret the mechanism of this favorable influ- 

 ence of the phenomenon tipoii the e\'oliUion of the infection. It 

 may follow a non-specific mobilization of cells of defense, as il- 

 lustrated by the work of Gay (1926) in Avhich there ^vas shown 

 that a "histological" monocytic barrier in the pleura indticed by 

 treatment Avith aleuronate protected against virtilent Streptococ- 

 cus Jiemolyticus. 



