4^ QUATERCENTENARY STUDIES IN PATHOLOGY 



3. That the injection of large doses of these toxic filtrates is capable 

 of stimulating the animal body to the formation of an antitoxin. 



4. That the neutralisation of the toxin by antitoxin is not merely due 

 to a precipitin reaction for {a) it occurs in vivo where no precipitin 

 reaction takes place, and {b) a serum with little or no antitoxic properties 

 may be capable of producing a marked precipitin reaction and vice versa. 



5. That neither antitoxic nor bacteriolytic actions play much part in 

 the protection afforded by an anti-plague serum. 



6. That the anti-microbial action of an anti-plague serum is, as was 

 first shown by Mark!, almost, if not entirely, due to a direct action of the 

 serum on the microbe, by means of which its negative chemiotaxis is 

 converted into a positive chemiotaxis, so that it no longer repels but 

 rather attracts the phagocyte. The substance in the serum producing 

 this action is thermostable, and has been variously named fixateur, 

 substance sensibilisatrice and incitor. 



(152) 



