n8 Immunity 



are, therefore, now concerned with a defect which, according 

 to the principles so ably worked out by Professor Carl 

 Weigert, is repaired by regeneration. These principles, in 

 fact, constitute the leading conception of my theory. If 

 after union has taken place, new quantities of toxin are 

 administered at suitable intervals and in suitable quantities, 

 the side-chains, which have been reproduced by the regen- 

 erative process, are taken up anew into union with the 

 toxin, and so again the process of regeneration gives rise to 

 the formation of fresh side-chains. In the course of the 

 progress of typical systematic immunization, as this is 

 practised in the case of diphtheria and tetanus toxin espe- 

 cially, the cells become, so to say, educated or trained to 

 reproduce the necessary side-chains in ever-increasing 



Fig. 10. Cells with various receptors or haptophorous groups of the 

 first order (a), adapted to combination with the haptophorous groups (6) 

 of various chemical compounds brought to them. It will be noted that 

 there is no mechanism by which the toxophorous elements of the mole- 

 cules (c) can be brought to the cell. 



quantity. As Weigert has confirmed by many examples, 

 this, however, does not take place by the simple replacement 

 of the defect; the compensation proceeds far beyond the 

 necessary limit; indeed, overcompensation is the rule. 

 Thus the lasting and ever-increasing regeneration must 

 finally reach a stage at which such an excess of side-chains 

 is produced that, to use a trivial expression, the side-chains 

 are present in too great a quantity for the cell to carry and 

 are, after the manner of a secretion, handed over as needless 

 ballast to the blood. Regarded in accordance with this 

 conception, the antitoxins represent nothing more than side- 

 chains reproduced in excess during regeneration and therefore 

 pushed off from the protoplasm and so coming to exist in the 

 free state." 



