INTRODUCTION I3 



entire thickness ol the abdominal wall. The readino of the in- 

 tensity and the record of the size of the reaction is made thereby 

 exceedingly easy. In some instances, Avhich remain ^vithout ex- 

 planation as yet, and also ^vhen the preparatory injection is made 

 subcntaneously, reactions may be obtained which do not extend 

 to the superficial layers of the skin and, therefore, appear as poorly 

 defined subciitaneons hematomas. In order to differentiate these 

 from brtiises, it is necessary to excise the suspected portion of the 

 abdominal w^all. In the gross, typical snbcutaneoiis reactions are 

 tniiform hemorrhages in nearly all layers of prepared sections of 

 the abdominal ^vall well demarcated from adjacent normal tissue. 

 The healing of the strongly hemorrhagic reaction is sIoav. 

 Sloughs which may form in about forty-eight hours after the in- 

 travenous injection are follo^ved by gradual separation and scar- 

 ring. The complete process of healing takes about ten days. This 

 coinse of events ^vas similarly described by Ecker and Welch 

 (1930), Gratia and Linz (1932c), Stolyhwo (1935), Apitz 

 (1933^) , Gerber (1936(7) , Kielanowski and Selzer (1934/;) . and 

 others. 



Bock (1932) attempted the percutaneous method of prepara- 

 tion. The ear of an albino rabbit ^\ as defatted whh soap and ether. 

 Cotton immersed in B. coli broth culture filtrate was applied to 

 the surface of the ear for one hour. Follo^vino the intravenous in- 

 jection of the same filtrate into another ear, he obtained, in many 

 instances, reactions of various intensity ranging from single l3luish 

 petechiae to diffuse dark blue infiltrations and necrosis of the ear. 

 Control defatted ears {i.e., not j^repared percutaneously ^vith the 

 filtrate) ga\e only hyperemia folloAving the intra\enous injection 

 of B. coli culture filtrate. Similarly, in a few experiments I at- 

 tempted to prepare the skin of the abdominal "\vall by vigorous 

 rubbing ^vith a sponge soaked in bacterial filtrate. Follo^ving the 

 intravenous injection of reacting factors there appeared infre- 

 quently scattered petechial lesions resembling purpura of men- 

 ingococcemia. The results ^vere rather irregular and apparently 

 depended upon variations in skin permeability. 



W'hen several sites of the skin of the abdominal ^vall are simul- 

 taneously injected, the subsequent intravenous injection of a 

 sufficient dose of bacterial filtrates elicits reactions of uniform 

 severity in the prepared sites. This is illustrated by the following 

 typical experiment (Shwartzman, 1928/;) : 



