CHEMICAL EQUILIBRIA 111 



partial neutralizations of the acids in order to find 

 out if they were dibasic, tribasic, etc., in which case 

 the evolution of heat was not constant at the different 

 measurements, but only as long as the same valency 

 of the acid was neutralized. For weak acids, such as 

 silicic or boracic acid, heat is evolved even after 

 equivalent quantities of bases (generally NaOH) 

 have been added if still further base is introduced 

 into the mixture. 



Ehrlich observed that the neutralization pro- 

 ceeded very irregularly, so that sometimes the second 

 addition of A neutralized more poison than the first 

 one (this he supposed to correspond to the greater 

 evolution of heat at neutralizing the second valency 

 of sulphuric acid as compared with the first). But 

 the very last portions of antitoxin always neutralized 

 very little of the toxin. Sometimes even the first 

 portion of the antitoxin had no neutralizing effect at 

 all. Different specimens of poison differed in the 

 highest degree from each other.' In order to 

 elucidate this question I asked Dr. Madsen to sum 

 up all his experiments from the Danish States Serum 

 Institute, which I subjected to calculation, using not 

 only the data for deaths between 3 and 4 days, as 

 was done before, but even those in which the death 

 of the guinea-pigs occurred at other times. The 

 decrease in weight of the animals was also used for 

 determining the toxicity of the injected mixture of 

 toxin and antitoxin. The results are given in the 

 table below. Two series of observations are given 

 there for the same poison, the first one (toxicity T x ) 



