1910-11.] The Mono-Molecular Reaction and Life-Processes. 627 
XLIII.— The Relation of the Mono-Molecular Reaction to Life- 
Processes and to Immunity. By John Brownlee, M.D., D.Sc. 
(MS. received January 9, 1911. Read January 9, 1911.) 
Some of the relationships, such as those* between toxins and antitoxins, 
discovered during the last twenty years have lately been investigated 
by Arrhenius. It has been found by this observer that many of these 
Diagram. I. 
processes can be adequately represented by the equations which govern 
homogeneous mass reactions ; for instance, the rates of the disappearance 
of diphtheria antitoxin and of typhoid agglutinin from the circulation are 
described at least empirically by such a formula (Diagram I.) (1). Some 
years ago, in a communication to this Society on the laws of epidemics (2), 
I showed that the course of an epidemic could be accounted for if the 
organism, having a high infectivity at the beginning of the epidemic, lost 
