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 158 



CHAPTEE XXVI 



1900. Immunity Natural immunity Artificial immunity . 168 



CHAPTEE XXVII 



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

 Senile atrophies Premature death Orthobiosis 

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



CHAPTEE XXVIII 



Researches on the intestinal flora Sour milk . . .196 



CHAPTEE XXIX 



1908. The Nobel Prize Journey to Sweden and Russia A 



day with L6on Tolstoi . . . . .199 



CHAPTEE XXX 



Intestinal flora Infantile cholera Typhoid fever Articles on 



popular Science ..... 206 



CHAPTEE XXXI 



1911. Expedition to the Kalmuk steppes to study tuberculosis 



Plague ....... 210 



CHAPTEE XXXII 



Further researches on the intestinal flora Forty Years' Search 



for a Rational Conception of Life . . . 220 



