I So LECTURES ON IMMUNITY 



The curve which represents the experiments of Madsen 

 on tetanolysin resembles very much that representing the 

 neutralisation of ammonia by means of boracic acid. It is 

 convex to the ;r-axis, which it never reaches. This prop- 

 erty indicates that the greater the quantity added, the 

 less is also the neutralising power of the same quantity 

 of antitoxin. But there is no reason to explain this 

 peculiarity by the hypothesis of Ehrlich, that in the toxic 

 solution exist side by side a large number of poisons. 



The equation which we used for the calculation of the 

 results, and which coincides very well with the experiment, 

 has the following form : 

 (Quantity of free lysin) x (guantity of free antitoxin) -j*~ 



K (quantity of bound toxin 2 ). 



According to the laws of physical chemistry this equa- 

 tion indicates that of one molecule of toxin and one 

 molecule of antitoxin there are formed two molecules of 

 the reaction-products. 



This reaction is therefore rather similar to that of alco- 

 hol and acid to give ester and water, one molecule of each 

 substance entering into the chemical equation of reaction. 

 In this case, if equivalent quantities of the reagents are 

 used, two-thirds of them are transformed to ester and 

 water, when the equilibrium is reached. The constant K 

 is in this case ^=0.25, about the double of that found for 

 tetanolysin. 



The constant K of the equation of equilibrium is altered 

 with temperature. When Madsen and I investigated this 

 phenomenon for the first time, we found a very great 

 increase in the proportion of i : 4.7 for the interval of tem- 

 perature 20 to 37.3 degrees. Later experiments have 



