122 CHEMICAL EQUILIBRIA 



and therefore takes away the first part of antitoxin 

 added and hinders it from neutralizing the poison. 

 It is quite clear that, in Madsen's case, the errors 

 of observation caused the spurious effect. Ehrlich 

 has also found " prototoxoids " only in some of his 

 diphtheria poisons, which differ rather much from 

 each other, and I have no doubt that the errors of 

 observation have caused the observed anomalies. 



The only poison for which Madsen, in his exten- 

 sive investigations on the neutralization of poisons, 

 has stated the presence of a prototoxoid is ricin. 

 This poison gives with its antitoxin a flocculent 

 precipitate of the compound, so that in Guldberg- 

 Waage's formula the concentration of this compound 

 enters in the form of a constant. The calculation 

 gives very concordant results with the observation, 

 if this peculiarity is observed. But before a pre- 

 cipitate is formed the compound remains in a 

 dissolved state and is probably nearly wholly dis- 

 sociated. Therefore the toxicity does not diminish 

 until enough antiricin is added to give a precipi- 

 tate. This limit is not very constant according to 

 Madsen's experiments, which may be due to super- 

 saturation or to the presence of foreign substances, 

 e.g. hydrogen ions, in different quantities. 



Even at the end of the neutralization Ehrlich 

 observed that the mixtures had lost their lethal effect 

 but were not innocuous and gave different symptoms 

 from the pure poison. It seems to me not very 

 strange that a poison gives different symptoms 

 according to its strength, for similar cases are 



