VITAL /V//-:.\VM//-:.Y.I or HACTERIA 95 



These derivatives Ehrlich calls prototoxins, deuterotoxins, and tri- 

 totoxins. 



All forms of toxins are supposed to consist of two modifications, 

 which combine in an equally energetic manner with antitoxin or with 

 suitable receptors in the cells, but differ in their resistance to heat and 

 other destructive agents. 



The less-resistant form passes readily into a toxoid substance which 

 has the same affinity for the antitoxin or the cell receptors as the original 

 toxin, but is not poisonous. The facts observed, Ehrlich thinks, are 

 best explained on the supposition that the toxic molecule contains two 

 independent groups of atoms, one of which may be designated as the 

 haptophorous and the other as the toxophorous group. It is by the 

 action of the haptophorous group that toxin unites with antitoxin or 

 the sensitive cell molecule. 



The toxophorous group is unstable, but after its destruction the 

 molecule still unites with the antitoxin or the sensitive molecule through 

 its retained haptophorous group. 



Specific antitoxins can be produced not only with toxins, but with 

 toxoids. 



Bordet believes, in contradistinction to Ehrlich, that toxin unites in 

 different multiples with antitoxin, so that the toxin molecule may have 

 its affinity slightly, partly, or wholly satisfied by antitoxin. Slightly 

 satisfied, it is still feebly toxic; combined with a larger amount of anti- 

 toxin, it is not toxic; but still may, when absorbed into the system, lead 

 to the production of antitoxin. Fully saturated, it has no poisonous 

 properties and no ability to stimulate the production of antitoxin. 



The most important of the extracellular toxins are those produced 

 by the diphtheria and tetanus bacilli. These are very powerful; 

 0.0000001 gram of the dried filtrate of a tetanus culture will frequently 

 kill a white mouse, while one-tenth of that amount of dried diphtheria 

 filtrate has killed a guinea-pig. 



The same bacterium may produce several entirely distinct toxins, 

 thus, according to Madsen and Ehrlich, the specific tetanus poison con- 

 sists of tw T o toxins, tetanospasmin and tetanolysin. To the first of these 

 the tetanic convulsions are due, while the second has a hsemolytic 

 action. 



When the tetanus toxins are placed in the blood tetanolysin largely 

 combines with the blood corpuscles, while the tetanospasmin combines 

 with the nerve cells. Each of these substances produces in animals a 

 specific antitoxin. To obtain diphtheria and tetanus toxins for injection 

 in animals the bacilli are grown in slightly alkaline beef-broth for from 

 seven to ten days. The broth is then filtered and preserved. Tetanus 

 toxin is produced under anaerobic conditions; diphtheria, under free 

 access of oxygen. (See special chapters on these bacteria.) 



Bacterial Endotoxins or Proteids. The bacterial poisons which reside 

 in the bodies of the bacteria are mostly yielded up only after the death 

 of the organisms. Here, in the invaded animal, the disease effects 

 are more closely associated with the actual presence of the bacteria 



