15<) LOCAL ILSSLE REACTIVITY 



In another series of experinicnls, skin sites injected with histamine were 

 re-injetted with calcium chloride and vice versa. The intervals of time be- 

 tween the two intradermal injections were one-hall hour, six, twenty-four aiul 

 forty-eight hours. The jirovocative intravenous injection of the bacterial fil- 

 trate was made twenty-four horns after the second intradermal injection. 



In a third series of experiments, histamine diluted 1:1000 was injected into 

 sites made reactive by preparatio.i with B. tyl>hosus ])reparatory factors. No 

 enhancement of the state of reactivity was observed. 



The last series of e.xperiments demonstrated that the addition ol histamine 

 to bacterial filtrates lacking in skin-preparatory factors failed to elicit the 

 state of reactivity to the phenomenon. These observatic^ns are in contrast 

 to a casual observation ol Gratia and Linz (1932^) in which an enhance- 

 ment of the state of reactivity is attributed to histamine. 



Acetylcholine: 



The skin-preparatory potency of acetylcholine was tested in dilutions 1:500, 

 1:1000, and 1:5000. Dilution 1:500 gave primary necrotic lesions. 



The addition of acetylcholine to B. typhosus "agar washings" filtrates in 

 various dilutions used for skin-preparation did not modify the typical re- 

 action of the phenomenon. 



AUylamine: 



The skin-preparatory potency of allylamine was tested in dilutions 1:1000, 

 1:2500 and 1:5000. 



The use of this substance as a preparatory agent appeared to be of spe- 

 cial interest because of recent observations of Mellon, Baker and Mcllroy 

 (1935) . These authors found that the intracutaneous injections of allylamine 

 in rabbits in the above dilutions promptly led to a necrotizing arteriolitis. 

 In its earliest stages, the outstanding features of the arteriolar disease are 

 hemorrhage into the wall and loss of its structure. Perivascidar changes con- 

 sist of mononuclear infiltration of tissue, polyblasts and formation of nodular 

 periarteritis. The picture, according to these authors, is strikingly similar to 

 that present in streptococcus human infections, which appear to have in their 

 background the phenomenon of hypersensitiveness. 



Croton oil : 



Croton oil was painted on the skin of the abdomen and one ear two to four 

 times at forty-eight-hour intervals. The first painting resulted in slight swell- 

 ing and the second one gave pronounced irritation and scab formation. The 

 provocative injections were given, following each of the paintings and at 

 the time when the scabs fell off and young granulation tissue was present. 



In some rabbits, the healed and the irritated sites received preparatory 

 injections of B. typhosus "agar washings" filtrates. The provocative injecticjn 

 developed in these prepared sites was distinctly limited to the site of the 

 injection. No extension of the reaction was noticed along non-prepared 

 irritated sites and the non-prepared sites of granulation tissue. 



