46 EVOLUTION OF THE INFECTIOUS DISEASES 



This fact agrees with the observation of L. Martin 1 that in 

 mild cases of disease immunity is established more rapidly 

 than in severe cases. 



We may thus consider as proved: 



1. That a certain pathogenic dose of diphtheria toxin is 

 fixed by the cellular tissues of the guinea-pig and that it is 

 retained in place eight or ten days without being either 

 neutralized or transformed. 



2. That immunization or, in other words, the excess pro- 

 duction of the "normal antibody" is inversely proportional 

 to the intensity of the reaction and to the gravity of the 

 lesion. 



These facts which do not accord with the theory of Ehrlich 

 are very easily explained in the light of experiments con- 

 cerning the nature and properties of mixtures of toxins and 

 antitoxins. We have seen in fact 2 that diphtheria and tetanus 

 antitoxins as well as antiricin can fix their toxins en surcharge; 

 that is to say, in a quantity greater than they can neutralize. 



The passage into the wash water of tetanus toxin fixed 

 en surcharge by the nervous tissue in vitro 3 as well as the 

 toxicity of the edematous fluid in the experiment above are 

 explained very simply in the following manner: 



Normal antibody contained in the nervous cells or in the 

 cellular tissue (diphtheria in a guinea-pig, horse or man) can 

 neutralize a definite quantity of toxin. The product of this 

 combination is neutral for the cell and if the quantity does 

 not exceed its digestive capacity, the cell digests it, eliminates 

 it and reproduces the substance neutralized in a little larger 

 quantity than it normally contained. The cell will then be 

 capable of neutralizing and digesting without difficulty a 

 larger quantity of toxin. In this way it will establish a 

 certain local immunity and the tissue so immunized will give 

 a Schick reaction negative for a dose of toxin which otherwise 

 would give a positive reaction. But we have seen that the 

 normal antibody can fix more toxin than it can neutralize 



1 Bull, med., 1917, 10 fevrier. 



2 Danysz, J. : Les proprietes et la nature des melanges de toxines avec 

 leurs antitoxines, Ann. de 1'Inst. Pasteur, mai, 1902. 



3 Danysz, J.: L'etude de 1'action de la toxine tetanique sur la sub- 

 stance nerveuse, Ann. d. 1'Inst. Pasteur, 1899, p. 156. 



