THE THEORY OF TOXIC ACTION. 161 



death from its general effects, often the most acute and widespread 

 necrosis may occur in a few hours round the site of inoculation. 



The Theory of Toxic Action. While we know little 

 of the chemical nature of any toxines we may, from our 

 knowledge of their properties, group together the tetanus 

 and diphtheria poisons, ricin, abrin, snake poisons, and 

 scorpion poisons. Besides the points of agreement already 

 noted, all possess the further property that, as will be after- 

 wards described, when introduced into the bodies of sus- 

 ceptible animals they stimulate the production of substances 

 called antitoxines. The nature of the antagonism between 

 toxine and antitoxine will be discussed later. Here to 

 explain what follows it may be stated (i) that the molecule 

 of toxine most probably forms a chemical combination with 

 the molecule of antitoxine, and (2) that it has been shown 

 that toxine molecules may lose much of their toxic power 

 and still be capable of uniting with exactly the same propor- 

 tion of antitoxine molecules. From these and other circum- 

 stances Ehrlich has advanced the view that the toxine mole- 

 cule has a very complicated structure, and contains two atom 

 groups. One of these, the haptophorous (an-rciv, to bind to), 

 is that by which combination takes place with the antitoxine 

 molecule and also with presumably corresponding molecules 

 naturally existing in the tissues. The other atom group 

 he calls the toxophorous^ and it is to this that the toxic 

 effects are due. This atom group is bound to the cell 

 elements, e.g., the nerve cells in tetanus, by the haptophor- 

 ous group. Ehrlich holds that the toxophorous group is the 

 more complicated and also the less stable. It is known 

 that, for instance, a diphtheria toxine obtained by the filtra- 

 tion of a bouillon culture loses its toxicity when subjected 

 to such physical agencies as light and heat, and to certain 

 chemical substances. Ehrlich explains this on the theory 

 that the toxophorous group undergoes disintegration. And 

 if we suppose that the haptophorous group remains un- 

 affected we can then understand how a toxine may have 

 its toxicity diminished and still require the same proportion 

 of antitoxine molecules for its neutralisation. To the bodies 

 ii 



