go BACTERIOLOGY 



toxin of the disease, the introduction of the toxins of a 

 disease into a susceptible animal having been found to 

 give rise to an elaboration of antitoxin just as does an 

 attack of the disease. 



The therapeutic action of antitoxin is essentially a 

 chemical one, depending upon the affinity between the 

 antibodies produced by the cells of the organism and the 

 toxin produced by the germs. The product of such 

 chemical union of toxin and antitoxin is a harmless 

 substance, just as is the product of the chemical action 

 which takes place between the ordinary inorganic poi- 

 sons and their antidotes, of which we study in toxi- 

 cology. 



It is probable that the toxin also has an affinity for 

 the tissue cells of the body, and combines with them 

 somewhat less readily than with antitoxin. When such 

 union takes place, it becomes necessary for larger quan- 

 tities of antitoxin to be produced or introduced from 

 without in order to cause the toxin to leave the tissue 

 cells which they tend to destroy, and unite with the 

 antitoxin which renders them inert. We can, there- 

 fore, readily understand the necessity for the early ad- 

 ministration of antitoxin, and also of the administra- 

 tion of larger doses when not given early. 



It is probable that the affinity of toxin for tissue cells 

 is greater hi some cases than in others. This is, doubt- 

 less, especially true of the toxin of the tetanus germ, 

 for the cells of the central nervous system, and accounts 



