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Drs. C. J. Martin and T. Cherry. 



of operation constant is indicated. The thick line separates off the 

 fatal results from those in which the rabbits lived. All other 

 factors were kept constant. The solutions were mixed in the vary- 

 ing proportions and stood at laboratory temperature (20 23 C.). 

 At stated intervals, by a stop watch, portions were pipetted off, and 

 the reaction terminated by rapidly raising the temperature to 68 C. 

 in a water bath. They were kept at this temperature for 10 minutes, 

 cooled, and kept for injection. 



In our experiments with diphtheria we allowed abundance of 

 time, 2 hours, for the reaction between the toxin and antitoxin to 

 take place. The surplus of antitoxin was also large, so that the 

 active masses were considerable and the temperature was favourable, 

 via 30 C. (Protocol III). We have not yet determined the in- 

 fluence of temperature upon the rapidity of the reaction, but our 

 results so far seem sufficiently conclusive to decide the question and 

 leave no room for doubt that the antagonism between the toxins of 

 diphtheria and snake venom and their relative antitoxin is due to 

 a direct chemical action which takes place between them. Further, 

 that the opposite conclusion come to by Calmette, and presumably 

 those of Wassermann, Nikanarow, and Marenghi were due to their 

 disregard of the value of time as a factor in such chemical action. 



