CONTENTS 
Page. 
Preface 3 
Acknowledgment 5 
Ehrlich’s side-chain theory of immunity. 11 
Phagocytosis 11 
Side chains . 12 
Eeceptors 13 
The toxin molecule 13 
Haptophore group 13 
Toxophore group 13 
Toxoids 14 
Antitoxin. Free receptors 15 
Origin and distribution of receptors 15 
Cytolysins 16 
Amboceptors 16 
Complement 16 
Welch’s views 16 
The immunity unit 18 
Definition 18 
Roux’s method of measuring antitoxin 19 
Behring’s standard 21 
Ehrlich’s earlier methods 21 
The antitoxin unit 21 
The immunity unit 21 
The toxine as a standard of measurement 22 
The antitoxin as a standard of measurement 23 
The glycerinated serum 23 
The powdered serum 24 
The constitution of the toxine and its relation to antitoxin 25 
The toxin 25 
Prototoxin 25 
Dentrotoxin 25 
Tritotoxin 25 
The toxoid - 25 
The toxone - 26 
L° defined • 26 
L-r defined 26 
Minimal lethal dose (MED) defined 26 
“Spectra” 27 
The toxone zone . . 31 
Views of Arrhenius and Madsen 32 
V on Dungern’ s conclusions 33 
Calcar’s proof of the duality of toxin and toxone 33 
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