58 TOXINES AND ANT1TOXINES. 



and bases. If the alkaloids be mixed in the right proportion, 

 the curve can assume an exactly similar form. 



Even ARRHENIUS and MADSEN will admit the existence of 

 protoxoids, but EHRLICH shows mathematically that there must 

 also be other toxoids. 



He further succeeded in demonstrating, by calculation of the 

 L + value of a particular poison, that in this case the neutralisation 

 of the toxine by the antitoxine exactly corresponded with the 

 neutralisation of a strong base by a strong acid i.e., that its 

 course had to be represented by a straight line. It was also 

 possible to prove, in the case of this same poison, that the forma- 

 tion of tritotoxoids must have taken place in those parts of the 

 toxine possessing the weakest affinity. 



Again, it can be easily demonstrated that there can be no 

 change in the degree of affinity during the conversion of toxine 

 into toxoid. But since, now, a poison that has been allowed to 

 stand does show differences in its affinity, it follows that these 

 must have already been present in the fresh poison, in the toxine 

 condition, and at the same time it is evident that this proves 

 that there is a plurality of poisons. 



EHRLICH thus firmly maintains his opinion that even in fresh 

 diphtheria virus there are varieties of poison with different degrees 

 of affinity, which subsequently undergo a partial conversion into 

 toxoids with different degrees of affinity. 



EHRLICH also firmly maintains the existence of toxones as 

 primary decomposition products of the activity of the diph- 

 theria bacillus, upon which doubt had been thrown by ARRHE- 

 NIUS and MADSEN. In particular, the fact of the existence of 

 a poison without toxones shows that we cannot here be dealing 

 with a " residue of unneutralised poison" but with individual 

 substances possessing only a slight affinity for antitoxine which 

 are usually present. For if it were a question of conditions 

 of equilibrium these would occur in the case of all poisons. 

 Apart from this important extreme case without toxones, addi- 

 tional evidence against this view is furnished by the enormous 

 variation in the relative amounts of toxones, which may range 

 from to 300 per cent. 



A further argument in favour of definite existence of toxones 

 is their frequent diminution, "formation of toxonoids," as well 

 as their absolutely different physiological action (vide supra). 



EHRLICH concludes from his arguments that diphtheria virus 

 consists of at least three varieties of poison : 



