TOXIN AND ANTITOXIN 545 



We see, therefore, that the first step taken with the aid of Gruber's 

 hypothesis leads us astray. But when we attempt to see how the 

 antitoxin could act according to Gruber's scheme, we find ourselves 

 lost in a maze. The antibody secreted by the cell is to combine 

 with a collateral group b, of the toxin, leaving group a, which pri- 

 marily effected the anchoring of the poison, intact. How then is 

 any antitoxic effect to take place? One might perhaps assume that 

 by the occupation of group b, the toxin loses its toxicity through 

 some influence exerted on the toxophore group. The poison would 

 thus in a certain sense be changed into a toxoid by the occupation 

 of group b. In that case, however, the toxin with group b neutralized, 

 should still be able to excite the production of antitoxin, just as toxoids 

 do. As a matter of fact, this is not at all the case, for we know that 

 toxin neutralized with antitoxin has completely lost both its toxic 

 property and its power to produce antitoxin. This fact, which is 

 absolutely irreconcilable with a plurality of the haptophore groups, 

 is easily explained by my theory by a blocking of the haptophore 

 group of the toxin. 



We see, therefore, that Gruber's assumption leads to consequences 

 which are absolutely untenable. It certainly is far from being an 

 improvement on my theory. In general, also, the principles of 

 scientific investigation demand that we restrict ourselves to the 

 simplest explanations possible and only make use of more complex 

 ones if it is absolutely necessary. But there is not the least reason 

 for Gruber's assumption of several haptophore groups; on the con- 

 trary there are a large number of objections to it. 



By this I do not mean to say that in addition to the haptophore 

 and toxophore group the toxin molecule contains no other chemical 

 groups, such as amido or aldehyde groups, which are able to com- 

 bine with other bodies. I merely contend that these atomic groups 

 do not influence the specific immunizing process. 



To take a chemical example, it is possible by diazotizing all kinds 

 of amins to transform these into diazo combinations which, corre- 

 sponding to the original substance employed, contain other radicals 

 capable of reacting, thus COH, CN, OH, NO, etc. The specific prop- 

 erty of these substances, that is, the property of forming azo dyes, 

 is, however, connected exclusively with the N-N group. The reac- 

 tions which the other groups can enter into have nothing to do with 

 this specific reaction. I conceive the constitution of the toxins 

 to be similar in character. 



