INTRODUCTION 



less forces of which we are ignorant 1 and will remain 

 ignorant for a long time, things with which other beings 

 than ourselves may be perfectly familiar; for it is here 

 that we find that imperfection of our senses which does 

 not allow us to draw conclusions from ourselves as to 

 other beings which surround us. 



"Do not defend yourself against faith and confidence. 

 Life would be an immense dupery, the world in the midst 

 of which we exist would be a colossal absurdity, if the 

 earth were the only abiding place and if what is best in 

 us and among us, should be lost in universal nothingness. 

 The heavens teach not only the glory of God, they teach 

 also hope to all those who are worthy of hope." 



Madame Duclaux closes her account of Duclaux with 

 these words in which many of us will concur: "L'dme 

 la plus modeste, la plus desinteressee, et une des plus justes 

 de ce temps." 



The following translation, which I have made from the 

 eulogy on Duclaux, published in the Annales de V Insti- 

 tute Pasteur for May, 1904, and written, it is said, by 

 Dr. Roux, his former student and his successor as director 

 of the Pasteur Institute, will serve as a fitting close to 

 this introduction: 



"Once more the Pasteur Institute is in mourning. The 

 third of this month died Emile Duclaux, the director of 

 this Institute, the founder of these Annales. 



"In less than a year, Nocard and Duclaux have been 

 taken from us! 



"All those who have frequented the Pasteur Institute 



1 How right he was must now be apparent to every one. Since these 

 thoughts were expressed in 1901 has come most of our knowledge of the 

 radio-active substances uranium, ionium, radium, actinium, thorium 

 and their emanations and all of those revolutionary ideas on the nature 

 of electricity, the structure of matter and the constitution of the universe, 

 which now fill the minds of scientific men with awe and wonder. 



