DIPHTHERIA 



47 



and the more it fixes, the more difficult it is for the cell to 

 transform and eliminate the compounds thus formed. The 

 cell may then succumb to the task, that is to say, to a veri- 

 table indigestion and may even become incapable of repro- 

 ducing antibodies in excess. 



It is useless to complicate the problem by assuming with 

 Ehrlich the existence in every toxin of a haptaphore group 

 which is exclusively immunizing and of a toxophore group 

 which is exclusively pathogenic, but we may certainly con- 

 clude from what precedes that the same substance will cause 

 one or the other of these reactions following doses measured 

 according to the degree of sensitiveness of the animal, that, 

 in a word, the immunizing or pathogenic reaction is a func- 

 tion of quantity and not of quality. 



We may represent the process which can go on in the 

 edematous tissues of the above experiment according to the 

 following scheme: 



T. TO), 



T, toxin; AT, antitoxin. 1, 'pathogenic compound; the antibody is 

 surcharged with toxin; 2, 3, intermediate compounds; 4, non-pathogenic 

 compound; the antibody has fixed the quantity of toxin necessary only 

 to produce an immunizing reaction. 



Between the two extremes, all intermediary steps are 

 possible but the quantity of toxin which an antibody can fix 

 en surcharge is not boundless and certain facts lead us to 

 suppose that this faculty of a tissue to fix larger or smaller 

 quantities of antigen depends not only on the local condition 

 of this tissue but rather on the general state of the organism. 

 Thus a dose of toxin fatal for a guinea-pig in three or four 

 days will produce on the second day an edema less volu- 



