RELATION OF TOXINES TO ANTITOXINES. 57 



throw of the side-chain theory as a whole. These have been so 

 completely answered and demolished by EHRLICH l that we can 

 refrain from discussing them individually here. 



At first sight the objections of ARRHENIUS and MADSEN to 

 EHRLICH'S theory of the manifold nature of diphtheria virus 

 appear to be much more important, since they are based on the 

 unquestionable results of experiments. This is another instance, 

 however, that in dealing with the theory of toxines there is 

 nothing against which we must guard more than too hasty 

 generalisations. 



EnRLiCH 2 maintains his position throughout in his reply to 

 the criticisms of ARRHENIUS and MADSEN. He, of course, admits 

 at once the correctness of the experimental proofs, though only 

 in the case of tetanolysine, whose instability and slow combining 

 power he himself had already recognised years ago. He refers 

 to one experiment in which the antitoxine activity after two 

 hours was forty times as great as immediately after the mix- 

 ture had been made. But EHRLICH contends that the facts 

 established in the case of this unstable, slowly -combining 

 poison ought not to be transferred to the extremely active 

 diphtheria virus, which combines rapidly (within a few minutes) 

 with the antitoxine, and for which alone his "spectra" have 

 been made. 



In his reply he once more repeats, very forcibly, the reasons 

 that led to the development of his conception of the complex 

 structure of diphtheria virus, and cites in support of it numerous 

 separate facts, some of which were previously unpublished. 



It would take too long to deal with all his reasons again, since 

 we should have to repeat nearly the whole of what we have 

 said about toxoids and toxones. Hence we will only mention a 

 few of them : 



The conclusion that there are toxoids of different degrees of 

 affinity follows inevitably, from the fact that the toxicity shows 

 a gradual decrease while the amount of antitoxine required for 

 neutralisation remains constant. EHRLICH cites the simple 

 example of the neutralisation of two distinct alkaloids e.g., 

 quinine and codeine, which have a different affinity for hydro- 

 chloric acid as evidence that we are here dealing with neutral- 

 isation limits, quite analogous to those which ARRHENIUS and 

 MADSEN regarded as states of equilibrium between weak acids 



1 Ehrlich, "Toxin und Antitoxin," Munch, med. Woch., 1903, No. 33-4 

 (reprint). 



2 Ehrlich, " Ueber d. Giftcoraponenten des Diphtherietoxins," BerL klin. 

 Woch., 1903, No. 35 (reprint). 



