PREFACE 



THE following pages contain a summary of six lectures 

 on the Immunity Reactions delivered at the University of 

 California, in Berkeley, California, during the summer 

 session of 1904. The object of the lectures was to illus- 

 trate the application of the methods of physical chemistry 

 to the study of the theory of toxins and antitoxins. The 

 idea that the reciprocal action of toxin and antitoxin is 

 of the same nature as a chemical reaction is nearly as old 

 as the study of these phenomena, which was inaugurated 

 by the discovery of the diphtheria antitoxin by Behring 

 and Kitasato in 1890. The German school, led by Ehrlich, 

 the renowned Director of the Prussian Serum Institute in 

 Frankfort-on-the-Main, has in particular done much work 

 in support of the opinion that the interaction of toxin and 

 antitoxin is of the nature of a chemical reaction ; whereas 

 the French school, led by Metschnikoff, tried to show that 

 the effect of an antitoxin is chiefly of physiological order, 

 an antitoxin was supposed to stimulate in some way the 

 organic tissues in their struggle against the attack of the 

 poison. 1 



When Ehrlich succeeded in showing that the agglutinat- 

 ing action of ricin upon red corpuscles (erythrocytes) sus- 

 pended in a physiological salt-solution (0.9% NaCl) is 

 inhibited by the antibody, the antiricin, the notion 

 that a physiological effect is executed by the antibody was 



1 The first studies in this direction were carried out by Buchner (1893) 

 and Roux and Vaillard (1894). Cf. Chapter II. 



