

Fig. 12. A, section of skin site after preparation with B. typhosus filtrate almost 

 completely neutralized by homologous antitoxic horse serum, followed twenty-four 

 hours later by intravenous injection of 25 reacting units of same filtrate. Four hours 

 after intravenous injection there were only slight inflammation and moderate vascular 

 congestion. B, section of skin site after preparation with non-neutralized B. typhnsus 

 filtrate, followed twenty-four liours later by intra\enous injection of 25 reacting 

 units of same filtrate. Four hours later tlie skin presented typical phenomenon, with 

 marked hemorrhage and inflammatory reaction. (Gerber, 19360. ) 



