TOXINS 123 



specific nature. That they are produced by synthesis can be 

 shown by growing the bacteria on Uschinsky's or similar media, 

 which contain no proteids, carbohydrates, or fats, but merely 

 simple organic and inorganic salts of known composition ; on 

 these media the bacteria produce their specific toxins, which 

 must, therefore, be synthesized. 1 Furthermore, diphtheria 

 toxin is essentially the same no matter on what sort of medium 

 it is grown, whereas ptomai'ns vary with the nature of the 

 substance from which they are produced. Toxins are true 

 secretions of bacterial cells, just as trypsin is of pancreatic cells, 

 or thyroiodin of thyroid cells. Anti-bodies can be produced 

 against toxins, but not against ptomains. 



Ehrlich's Conception of the Nature of Toxins. 

 Chemical studies of toxins being impossible, we have been 

 obliged to study them through their physiological effects, just 

 as we have obtained information concerning enzymes through 

 their specific actions. In this way Ehrlich has obtained well- 

 crystallized ideas concerning the structure of toxins, as well as 

 the manner in which they act, which may be briefly summarized 

 as follows : Each toxin molecule consists of a large number of 

 organic complexes grouped, as in other organic compounds, as 

 side-chains about a central chain or radical. One or more of 

 these complexes has a chemical affinity for certain chemical con- 

 stituents of the tissues of susceptible animals, with which the toxin 

 molecule unites ; this binding group is called the haptophore 

 (meaning " bearing a bond " ). Another side-chain or group of 

 side-chains exerts the injurious effects upon the tissue to which 

 the molecule has been bound by the haptophore, and cannot pro- 

 duce these injurious effects unless it has been so bound. This 

 injury- working group is called the toxophore. An animal is 

 susceptible to a toxin only when its cells contain substances 

 which possess a chemical affinity for the haptophore groups of 

 the toxin, and also substances which can be harmfully influenced 

 by the toxophore groups. Tetanus toxin, for example, owes its 

 effects to the fact that nervous tissues contain chemical sub- 

 stances having a strong affinity for the haptophore group of 

 tetanus toxin, and also substances that can be attacked with 

 serious results by the toxophore group of the toxin. The nature 

 of the changes brought about by the toxophore groups of toxins 

 is not understood ; there are many resemblances to the action 

 of enzymes, but the analogy is by no means complete. We find 

 perhaps the closest analogy to the enzymes in the toxic sub- 

 stances that destroy red corpuscles and bacteria (hemolysins, 

 1 Zinno could not confirm this observation (Cent. f. Bakt., 1902 (31, Abt. 1), 42). 



