FOREWORD 



Tlie problem of the mechanism of death and that of 

 the mode of action of poisonous substances have been 

 among the favorite subjects of our program of publica- 

 tion. We, therefore, welcome the opportunity of editing 

 this monograph. 



The author 's forty years of laboratory experience with 

 bacteria and his constant interest in the fundamental 

 problems of biology recommend him both for knowing 

 '^the facts" and for being one of those who try to ''get 

 to the bottom of things." 



His notion that "cell mechanisms," corresponding to 

 the various physiological functions, are affected indi- 

 vidually by disinfectants, and that injury and death are 

 the result of an impairment or a destruction of some of 

 these mechanisms, will give rise, we expect, to fruitful 

 discussions. 



New arguments are advanced, in the tirst part of the 

 monograph, in favor of the idea that the survivor curves 

 of bacteria — and, according to the author, of unicellu- 

 lar organisms in general — are exponential. There are 

 many opponents of this idea (among them the present 

 editor). Professor Rahn's arguments will force these 

 opponents to give thought to some aspects of the subject 

 which they might otherwise overlook. 



The author's attempt to bring some system into the 

 study of the action of that group of substances which 

 stop, delay, or otherwise impede the activity of bacteria, 

 without killing them, will be of particular interest to 

 those who know how much of a "mix-up" this subject is. 



June 1, 1945 



Saint Louis, Missouri 



B. LUYET. 



