FACTORS OF PATHOGENICITY AND INFECTION 239 



place. Db'nitz, 9 for instance, has shown that within four to eight 

 minutes after the injection of certain toxins, considerable quantities 

 will have disappeared from the circulation. Conversely, Metchni- 

 koff 10 has observed that tetanus toxin injected into insusceptible 

 animals (lizards) may be detected in the blood stream for as long 

 as two months after administration. 



9 Ddnitz, Deut. mod. Woch., 1897. 



10 Metchnikoff, "L'immunite dans les malad. infect." 



