CONTENTS xix 



CHAPTER XXV 



PAGE 



1894. Pfeiffer's experiments The Buda-Pest Congress 

 Extracellular destruction of microbes Reaction of the 

 organism against toxins Dr. Besredka's researches 

 Macrophages The Moscow Congress Bordet's experiments 168 



CHAPTER XXVI 



1900. Immunity Natural immunity Artificial immunity . 168 



CHAPTER XXVII 



1893-1905. Private sorrows Death of Pasteur Ill-health 

 Senile atrophies Premature death Orthobiosis 

 Syphilis (1905) Acquisition of anthropoid apes (1903) . 181 



CHAPTER XXVIII 



Researches on the intestinal flora Sour milk. . .196 



CHAPTER XXIX 



1908. The Nobel Prize Journey to Sweden and Russia A 



day with Leon Tolstoi . . . . .199 



CHAPTER XXX 



Intestinal flora Infantile cholera Typhoid fever Articles on 



popular Science ..... 206 



CHAPTER XXXI 



1911. Expedition to the Kalmuk steppes to study tuberculosis 



Plague . . . . . . .210 



CHAPTER XXXII 



Further researches on the intestinal flora Forty Years' Search 



for a Rational Conception of Life . . .220 



