38 IMMUNE SERA 



elusion that diphtheria poison is a very complex 

 substance, containing toxin, toxon, and perhaps still 

 other primary secretion products in addition to the 

 various secondary modifications of these, toxoids, 

 toxonoids, etc. It is difficult to escape the feeling 

 that the existence of some of these hypothetical 

 substances is more apparent than real. 



Views of Arrhenius, Bordet and Others. Bordet 

 and others refuse to accept Ehrlich's views and 

 the whole matter is still unsettled. Thus the exist- 

 ence or non-existence of toxons has excited a great 

 deal of discussion among investigators. 



The great Swedish chemist, Arrhenius, has given 

 much attention to the toxins; and has applied 

 the principles of physical chemistry to the toxin- 

 antitoxin reaction. It is, of course, well known 

 that a solution of a compound such as sodium 

 chloride represents not only NaCl in solution, 

 but also sodium ions and chlorine ions. There is 

 a certain amount of dissociation going on hand in 

 hand with a combination of the two components. 

 The degree of this varies with the temperature and 

 the dilution of the substances. Arrhenius believes 

 that the same process goes on with the toxin- 

 antitoxin combination and that such more or less 

 dissociated compounds give rise to the effects 

 Ehrlich ascribes to the toxon. There is, however, 

 no direct evidence that the combination of toxin- 

 antitoxin is reversible. It is true that Morgenroth 



