

Ik.. 13. .J, section ot skin site six hours alter intradermal injection of typhoid 

 Ijacillus filtrate in dilution of 1:150. There is only slight inflammation, with occasional 

 dilatation of vessels. B, histologic appearance of typical phenomenon after skin prep- 

 aration with typhoid bacillus filtrate in dilution of 1:150, followed by intravenous 

 injection of 25 reacting units of same filtrate. Striking hemorrhage and vascular en- 

 gorgement are evident. (Gerber, 19360.) 



