Ill 



mal serum containing several different kinds of pro- 

 teids, is also present a little amount of a body with 

 neutralising action upon tetanolysin, while the usual 

 proteids only to a certain degree decrease the action of 

 tetanolysin. 



In the case of chemical processes of dissociation, K 

 is changed with the temperature and also in this case 

 the decomposition of the combination toxin-antitoxin 

 increases with increasing temperature as in most of the 

 phenomena of dissociation. By means of a quantitative 

 investigation of this change it is possible to determine 

 tlie amonns of heat (WJ set free, when a grammolecule 

 of toxin combines with a grammolecule of antitoxin. 

 For this the formula of van't Hoff is valid: 



d log. nat. K W 



dt 1,99 T 2 



For the purpose of this determination experiments 

 with the same toxin and antitoxin were made at 20 

 and 37 C. All the concentrations used at the low tem- 

 perature were double as great as at the high tempera- 

 ture and the experiments at the low temperature were 

 undertaken once during 6 hours, another time during 

 7,5 hours, while the test tubes at the high temperature 

 were kept a 37,2 C. for only one hour and then were 

 put into the ice safe. 



As the experiments give good illustrations of the 

 exactitude, which can be obtained, following details 

 shall be communicated. The series of experiments at 

 20 C. were carried out with solutions of toxin which 

 were 0,2% and 2%, and which per cc. contained the 

 following amounts of a V8o/o antitoxin solution: 0,1, 

 0,2, 0,4, 0,7 and 1 cc. The relative toxicity of the diffe- 



73 



