128 CHEMISTRY OF BACTERIA AXD THEIR PRODUCTS 



age processes from the medium upon which the bacteria grow, and 

 the same ptomains can be produced by several different kinds of bac- 

 teria, the toxins are synthetic products of absolutely specific nature. 

 That they are produced by synthesis can be sho\ra by growing the 

 bacteria on Uschinsky's or similar media, which contain no proteins, 

 carbohydrates, or fats, but merely simple organic and inorganic salts 

 of known composition ; on these media the bacteria produce their spe- 

 cific toxins, which must, therefore, be synthesized.''^ Furthermore, 

 diphtheria toxin is essentially the same no matter on w^hat sort of 

 medium the bacteria are grown, whereas ptomains vary wdth the 

 nature of the substance from which they are produced. Toxins are 

 true secretions of bacterial cells, just as tiypsin 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 informa- 

 tion concerning enzymes through their specific actions. In this way 

 Ehrlich developed well-crystallized ideas concerning the structure 

 of toxins, as well as the manner in wliich 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 constituents of 

 the tissues of susceptible animals, wdth which the toxin molecule 

 unites; this binding group is called the haptopJiore (meaning "bear- 

 ing 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 produce these injurious effects unless 

 it has been so bound. This injury-working group is called the toxo- 

 phore. An animal is susceptible to a toxin only when its cells con- 

 tain substances which possess a chemical affinity for the haptophore 

 groups of the toxin, and also substances which can be harmfully influ- 

 enced by the toxophore groups. Tetanus toxin, for example, ow^es its 

 effects to the fact that nervous tissues contain chemical substances 

 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 en- 

 zymes in the toxic substances that destroy red corpuscles and bacteria 

 (hemohjsi)is, harfcrioh/si'tis) , wliit'li will be considered in another 

 ])lace. The immunity against toxins and enzymes seems to be pro- 

 duced by identical processes, which consist in an overproduction of 



oslladlcy, Jour. Infect. Dis.. lOO", Suppl. TTT, ]>. 05. 



