iv PREFACE 



to Pasteur's biography. It has been my aim to set 

 forth, briefly and simply, the chief discoveries of 

 this great investigator, to describe his methods of 

 critical experimental enquiry, and to show how he 

 was led on, step by step, from one field of research 

 to another, making discoveries of the highest impor- 

 tance in every field he traversed. I have endeav- 

 ored also to give an idea of Pasteur's personality 

 and its relation to his scientific work. So remark- 

 able and inspiring a career as that of Pasteur can- 

 not be too widely known, and I make no apology, 

 therefore, for adding to the number of books upon 

 this great man. 



I am indebted to Dr. T. D. Beckwith of the 

 Department of Bacteriology of the University of 

 California for reading the whole manuscript, and 

 to Dr. J. H. Hildebrand, Professor of Chemistry 

 in the same institution, for reading the chapters 

 which deal with Pasteur's chemical researches. 



S.J.H. 



UNIVERSITY OF CALIFORNIA, 

 BERKELEY, CALIFORNIA. 



