TOXINS AND ANTITOXINS. 25 



attach themselves to the complex molecules of 

 albuminoid substances, such as the different 

 toxins. 



Ehrlich supposes, as we have already seen, that 

 a toxin contains two special groups — a toxophore 

 group, which poisons, and a haptophore group, 

 which combines with the receptor. According to 

 this theory, the toxophore group of a toxin can act 

 on an organism only when the haptophore group 

 of the toxin encounters a suitable attachment or 

 receptor. 



The receptors attached to the living proto- 

 plasmic molecule attract the toxin, just as a light- 

 ning-rod attracts the lightning. 



It is hence clearly proved that the toxigenic 

 poisons exert their noxious action on the cellular 

 elements of sensitive organisms, by entering into 

 combination with these. 



Experience has shown that they attach them- 

 selves, in a most rigorously elective manner, to the 

 tissues, and rapidly disappear from the general 

 circulation. Numerous facts, clearly established, at- 

 test the reality of this fixation or attachment. 



It is thus that von Behring and Wernicke * 

 sought to ascertain the quantity of antitoxin (we 

 will see farther on that this name is given to those 

 substances which neutralize the activity of toxins 



♦ Von Behring and Wernicke; Zeitschrift fur Hygiene, xii. 



