458 MICROBIOLOGY 



elusions are quite widely if not generally accepted not only in 

 connection with the production of antitoxin and its standardi- 

 zation but also in explaining the phenomenon of lysis as ex- 

 hibited in hemolysis, cytolysis and bacteriolysis. 



According to Ehrlich, toxins and antitoxins neutralize 

 each other after the manner of chemical reagents. This belief 

 is largely based on the observations that neutralization takes 

 place more rapidly in concentrated than in weak solutions, 

 and that warmth hastens and cold retards neutralization. 

 From these observations Ehrlich concluded that toxins and 

 antitoxins act as chemical reagents in the formation of double 

 salts, a molecule of the poison requiring an exact and con- 

 stant quantity of the antitoxin in order to produce a neutral 

 or harmless substance. .This implies that a specific atomic 

 group in the toxin molecule combines with a certain atomic 

 group in the antitoxin molecule. 



He also found that the toxins are not simple bodies, but 

 easily split or modified into other substances which differ 

 from each other in the avidity with which they combine with 

 antitoxin. These derivatives of toxin he calls prototoxins, 

 deuterotoxins, and tritotoxins. 



Ehrlich 's studies of the toxin- antitoxin reaction were 

 directed along the line of his former investigations into the 

 manner of cell-nutrition,* namely, that as nutritious sub- 

 stances are brought into workable combination with the cell 

 by means of the atom-groups corresponding to side chains, so 

 toxins exert their deleterious action only because the cells 

 possess side chains by means of which the toxin can be chem- 



* Ehrlich ("Das Sauerstoffbediirfniss des Organismus," Berlin 

 1885) held the opinion, that for the cells to be nourished, the 

 nutritive substance must enter into chemical combination with some 

 elements in the cell protoplasm. The large number of chemical sub- 

 stances which act as nutriment led him to believe that the complex 

 prot plasmic molecules of the cells were made up of a central atom- 

 group (Leistungs-Kern) upon which depended the activities of the 

 cell and a great variety of side chains which enabled the cell to enter 

 into combination with food and other substances that were brought 

 to it in the circulation. This can be illustrated graphically by the 



