ALEXIN ABSORPTION. 413 



with exudate, whereas it is very much retarded by the normal 

 serum. 



Peritoneal exudate, then, favors the demonstration of alexic 

 activity. Thirteen years ago the " reactivation" of heated cholera 

 serum by fresh normal serum was demonstrated by one of us. It 

 was also shown at the time that bacteriolysis is due to the collabo- 

 ration of the specific antibody and the alexin. The granular trans- 

 formation of vibrios, which is indicative of bactericidal power, 

 generally occurs more rapidly in the peritoneal cavity than in 

 mixtures in vitro containing serum. The reason for this is simply 

 that the antagonistic property of heated serum retards bacteriolysis 

 more markedly in vitro than in vivo. 



It is evident that the presence of an antagonistic property must 

 have been a great source of error in many experiments and in 

 particular in those based on the principle of specific absorption 

 and those dealing with the multiplicity of active substances in a 

 given serum; obvious examples of this error are present in experi- 

 ments dealing with the discussion concerning the unity or multi- 

 plicity of alexins. 



