172 LOCAL TLSSIIE REACTIVITY 



suited in as severe a reaction as tliat seen Avitli the use ol llUrates 

 which produced much greater degrees of inflaniniation with skin 

 preparation. ()I)vi()iisly the determining factor in the production 

 of the phenomenon is not in the inflammation attendant on skin 

 jireparation ])ut rather in the a( tual preparedness of the skin. The 

 degree of inllannnation occurring with skin {^reparation is no index 

 of the state of preparedness of the skin. Thus, in the experiments 

 in which forty-eight hours elapsed after the skin preparation, the 

 inllannnation was still severe, yet the state of reactivity of the skin 

 ^vas so low that it required fotir times the usual cpiantity of liltrate 

 to elicit the phenomenon. Moreover, the degree of inflannnation 

 prcxluced Avith skin jjrejjaration did not determine the extent of 

 the inflammatory reaction seen on production of the pfie- 

 nomenon. 



It is still tmknown ^vhat substances in the iUtrate are responsi- 

 ble for the inflammation. Ho^vever, since intradermal injections 

 of a filtrate of high skin-preparatory potency result in minimal in- 

 flammation, no greater than that of the controls, the preparatcjry 

 factors are in themselves not responsible for the inflammation. 



It is significant that in Gerber's studies in ^vhich filtrates of high 

 skin-preparatory potency '^vere used so that only small quantities 

 were necessary, and the amoimt of non-specific irritating sub- 

 stances was clearly reduced, the absence of hemorrhage and 

 thrombosis ^vith skin preparation alone ^vas a constant feature. 

 Thus, the appearance of hemorrhage and thrombosis Avith ac- 

 centuation of the inflammation served to differentiate the phe- 

 nomenon from skin preparation c|ualitatively as ^vell as quantita- 

 tively. 



The cause of the hemorrhages could not be ascertained by this 

 author, morphologically. Although occasional ruptured capillaries 

 were seen in sections of skin showing the phenomenon, he cotild 

 not attribute the extensive hemorrhage to these alterations. 



Gerber was also impressed by the occurrence in the reaction 

 of the phenomenon of widespread thrombosis affecting chiefly 

 the veins. At a site of attachment of the thrombi no endothe- 

 lial alterations were noted by him. The affected vessels were 

 surrounded by thick collars of polymorphonuclear leucocytes; 

 these often infiltrated the entire wall of the vessel. Ghanges in the 

 elastica were absent. 



A])itz suggested that Dietrich's concept of endothelial hyjjer- 

 ac ti\ ity may serve to explain the origin cjj the thrombi obserxed in 



