XXX INTRODUCTION 



an annotated list of persons mentioned, a portrait of 

 Pasteur made from a bronze in my possession, several 

 from middle-period photographs and one from a photo- 

 graph taken in his old age. To these I have added two 

 portraits of Duclaux, one from a photograph made a 

 year or two after he became director of the Pasteur 

 Institute (about 1897), the other from an admirable oil 

 painting made by Ernest Bordes in the last year of his 

 life and purchased by the French Government for the 

 Pasteur Institute, both through the courtesy of Madame 

 Duclaux. For a third portrait of Duclaux the reader 

 may consult the Frontispiece in "Bacteria in Relation to 

 Plant Diseases," Vol. I, Carnegie Institution of Washing- 

 ton, 1905, where also may be found another portrait 

 of Pasteur and one of Roux. 



The greatest progress of bacteriology since this book 

 was written has been in the field that would have inter- 

 ested Pasteur most, namely, in that of immunology, 

 which now has its own text-books and journals. Read 

 in the light of the new knowledge, the Eighth Part of 

 this book seems very ancient history although it well 

 expresses the current ideas of twenty years ago and will 

 always serve as an important landmark. 



E. F. S. 



