198 LECTURES ON IMMUNITY 



antitoxin on the one hand and the products of their reaction 

 on the other hand, as the calculated figures show. These 

 are calculated from the equation valid for the neutralisa- 

 tion of tetanolysin, only the constant of equilibrium here 

 is about eight times lower than there ; in other words, the 

 reaction proceeds farther in the binding of diphtheria- 

 toxin than in the binding of tetanolysin. 



When the toxicity sinks below one, the animals under 

 experiment do not die after the injection of the quantity of 

 poison employed (o. I c.c.). By administering greater doses 

 it is still possible to kill the animals. But if the quantity 

 of antitoxin exceed a certain amount, the animals are not 

 killed (in short time, eight, days), but show other symptoms 

 of the disease ; after an incubation time of more than a 

 week paralysis occurs. Now Madsen and Dreyer l showed 

 that such paralysis is sometimes observed also after the 

 injection of a quantity of pure diphtheria-poison less than 

 the lethal dose. The free poison injected subcutane- 

 ously gives other symptoms, namely, necrosis and alopecia 

 at the site of injection. Ehrlich and his pupils now con- 

 tend that with mixtures of toxin and antitoxin which do 

 not kill the animals but produce paralysis, the local 

 effects at the site of injection are much less than after 

 the injection of the corresponding quantity of free poison, 

 whereas the paralysis is much stronger with the use of the 

 mixture than with the free poison; and therefore the 

 paralytic result is ascribed to a poison, toxon or epitoxin, 

 which remains after the neutralisation of the true toxin. 

 According to Madsen the difference observed depends 

 upon the following circumstances. The greater part of 



1 Dreyer and Madsen : Festskrift, Copenhagen, No. 5 (1902). 



