614 APPLICATION OF METHODS OF BACTERIOLOGY 



tetanus is characterized; to this latter the designation 

 " tetanospasmin" is given. Madsen's observations, further- 

 more, confirm the deductions of Ehrlich concerning the 

 molecular structure of bacterial toxins in general, to the 

 effect that the molecule of tetanolysin, like that of diph- 

 theria toxin, is a complex of at least two physiologically 

 unlike groups; the one, characterized by its marked com- 

 bining tendencies (for antitoxin), the so-called haptophore 

 group; the other, distinguished for its intoxicating quality, 

 the so-called toxophore group. 



Tetanus Antitoxin. The principles involved in the induction 

 of the antitoxic state against diphtheria are likewise applicable 

 to tetanus; in fact, the fundamental observations upon the 

 generation of antitoxin in the living animal body were made in 

 the course of studies on tetanus; they were subsequently ap- 

 plied to the study of diphtheria, with the results already noted. 

 It is needless to enter here upon the details essential to the 

 production of tetanus antitoxin; to all intents and purposes, 

 they are identical with those given in the section on diph- 

 theria. Briefly stated, animals may be rendered immune 

 from tetanus by the repeated injection of gradually increas- 

 ing non- fatal doses of tetanus toxin; when immunity is 

 established, the circulating blood contains a body, anti- 

 toxin, that combines directly with tetanus toxin in a test- 

 tube, and thereby renders it physiologically inactive (non- 

 intoxicating); and the serum of the immune animal is not 

 only capable of protecting non-immune, susceptible animals 

 from the poisonous action of tetanus toxin (within limits), 

 but also against the effects of the living tetanus bacillus as 

 well. 



Tetanus antitoxin, though the first antitoxin discovered 



