672 COLLECTED STUDIES IN IMMUNITY. 



ciated to so great a degree by diluting the mixtures. The process 

 reminds one in a way of the well-known chemical phenomenon of 

 hyclrolytic dissociation. To mention but a single example, acetic 

 acid and alcohol unite to form ethylacetate. Conversely, however, 

 when diluted with water, ethylacetate decomposes into its two 

 components, acetic acid and alcohol. If we regard the toxin as the 

 acetic acid, the antitoxin as the alcohol, and the neutral toxin-anti- 

 toxin mixture as the product of the two, ethylacetate, we get a good 

 picture of what occurs when we dilute the toxin-antitoxin mixture. 

 Our experiments show, then, that by diluting neutral toxin-antitoxin 

 mixtures it is possible to recover the two components, toxin and anti- 

 toxin, up to a certain point. Furthermore, the possibility of doing 

 this by dilution exists for only a comparatively short time. After 

 this the secondary tightening of the bonds effects such a firm union 

 that this mode of separating the two components does not avail. 

 By making use of special methods, however, it is possible, even after 

 a considerable time, to liberate the toxin from a neutral toxin-anti- 

 toxin mixture. This is well shown by the interesting experiments 

 recently published by Morgenroth. 1 This author showed that by 

 allowing hydrochloric acid to act on a neutral mixture of cobra 

 venom and its antitoxin, complete dissociation could be effected, 

 so that the entire amount of the two substances could be recovered. 

 Morgenroth rightly regards this demonstration as an important 

 argument in favor of the chemical theory of the toxin-antitoxin 

 reaction, and emphasizes the fact that this behavior in no way 

 contradicts the stereochemical conception formulated by Ehrlich. 



Conditions apparently are such that after the union has become 

 firm only the intense influence of powerful agents, such as hydrochloric 

 acid in the case before us, or ferments in the case of glucosides, are 

 able to effect dissociation. In contrast to this, we see that the di- 

 lution phenomenon studied by us is demonstrable only during the 

 stage of loose union, mere dilution being unable to effect dissociation 

 after the union has become firm. It is evident, from what has been 

 said, that it is impossible to analyze these reactions according to the 

 principle of the Guldberg-Waage law. Objection must also be made 

 to the attempts to view these relations from the standpoint of 

 colloid chemistry. These attempts grow out of purely external 



1 Morgenroth, Ueber die Wiedergewinnung von Toxin aus seiner Antitoxin- 

 verbindung, Berliner klinische Wochenschrift, 1905, No. 50. 



