362 LOCAL TLSSUE REACTIVITY 



reactivity. II a pai enteral injection ol tuberculin is made, the 

 tiiberctilous antigen may then combine with the active accjuired 

 anti-tiiberculous antibodies. This combination (jcctnTing intra- 

 \ascidarly may be responsible for severe hemorrhagic necrotic 

 and inflammatory lesions in the infected sites. It is obvious that 

 this type of reaction is necessarily specific inasmuch as an inter- 

 action must occiu" f)et\veen the antibodies actively acquired in the 

 cotnse of the infection with the bacterial antigen injected. 



Conversely, it is also consistent that reactions be obtained \vith 

 heterologous fjacterial antigens not related to the etiological 

 factor of the disease ^vhen the filtrates contain the actixe prin- 

 ciples of the phenomenon (hetero-allergic reactions discussed 

 above) . P. Bordet deser\es the credit for first calling attention 

 to the fact that these hetero-allergic reactions may depend on 

 the mechanism illustrated by the phenomenon of local tissue 

 reactix'ity. 



Furthermore, an indirect mechanism of production of focal 

 lesions in infected animals must be considered. The injection of 

 an inert colloidal sidjstance capable of producing profoinid shock 

 when introduced into the blood stream, may be expected to 

 bring about a release of active principles of the phenomenon 

 from the infected foci. These principles may, then, revert back 

 to the infected foci and produce the hemorrhagic lesions in them. 



Local reactions of bacterial allergy in relation to phenomenon : 



When the antigen injected into the skin of an infected animal 

 possesses active principles of the phenomenon, there is elicited 

 a state of reactivity to the active princij)les secreted by the in- 

 fected foci into the blood stream. Thus, a reaction at this site 

 is easily explained. 



Tid^ercidin, however, possesses a very low skin-preparatory 

 potency.^ A different explanation is, therefore, offered for tuber- 

 culin reactions. The local inflammatory reaction produced fjy 

 the interaction of the antibody with the tuberculin injected may 

 localize the active principles of the phenomenon from the blood 

 stream, as in Method 25 of Table x. Whilst the state of reactivity 



^ It was shown by me that the acti\e principles of the jjhenomenon present in 

 tiiberciiHn are more heat hihile tlian the tuberciihn |:)ropcr siiljstances. Boqnet 

 and Bretey (1933) lound that milieatcd culture liltrates ha\e (i\e times more 

 activity than the same filtrates heated to 120° c. for I/9 hour, as judged by skin 

 reactions and general toxicity for tuberculous guinea pigs. 



