CURATIVE ACT10X OF 8ERUMX. 307 



animal. Similar conditions were met in the neu- 

 tralization of diphtheria toxin by its antitoxin in 

 the body. Madsen, in performing what he called 

 "Curative Experiments in the .Reagent Glass/" 

 found that the longer tetanolysin had been in con- 

 tact with erythrocytes, the more antitetanolysin 

 was required to tear away the toxin from the cor- 

 puscles. Practical experience with diphtheria also 

 indicates that the longer the disease lasts the more 

 antitoxin is required for cure. 



The experiments just cited give us a clear con- Nature of 



, J . ,. Curative 



ception as to what is meant by the curative action Action. 

 of an antitoxin an action which consists not of 

 the neutralization of the circulating toxin, but of 

 the wresting away from the tissue of the toxin 

 which has been bound. Incidentally the circulat- 

 ing toxin is neutralized, and for this step, which 

 is essentially prophylactic in nature, the simple 

 equivalent of antitoxin is required. But for the 

 wresting of toxin from tissue cells not a mere 

 equivalent of antitoxin, but a great excess, is re- 

 quired, as shown by the experiments of Donitz and 

 of Madsen. 



When diphtheria or tetanus has advanced so far 

 that no amount of antitoxin will effect a cure, the 

 relation of the toxin to the cells has become some- 

 thing more than mere chemical union. Further 

 processes of a biologic or biochemic nature have set 

 in in which the toxin may have become an integral 

 part of the protoplasm, and the toxophorous group 

 may have begun its destructive action, whatever 

 the nature of this action may be. 



It is important to recognize that antitoxin can 

 not repair an injury already done by the toxin. 

 The repair of the injury depends on the recupera- 



