342 



STUDIES IN IMMUNITY. 



one-half hour. After 3 hours at 37C slight hemolysis is present only 

 in the tube at one-half per cent (complete hemolysis if the deposit of 

 such a suspension is used), which shows that not even at this tem- 

 perature is the toxic action of the "complement" entirely destroyed. 

 If we add 0.5 of a cubic centimeter of fresh guinea-pig serum to an 

 analogous series of tubes, it is found that hemolysis is all but com- 

 plete throughout the series, that is, only the slightest " plugging" 

 has occurred. The combining ability of the dog complement is 

 impaired equally with and proportionately to the toxic ability. 

 The tables follow: 



TABLE I. 



TABLE II. 



Represents the actual volume present. 

 TABLE III. 



