'I could not waste my time in going back upon things already accomplished.' 'No; but my desire is that someone else should consecrate his time to the work. And listen,' added this friend, with audacious frankness--'do you know by whom, in my opinion, this book ought to be written? By a man who, without having been in any way trained to follow in your footsteps, is animated by the most lively desire to understand the course which you have pursued; who, while living at your side, has been each day impregnated with your method and your ideas; who, having had the happiness of comprehending your life and its achievements, does not wish to confine the pleasure thus derived to himself alone.' 'Where, then,' interrupted Pasteur with a kindly smile, not without a tinge of irony, 'is this man, at once so happy, and so impatient to share his happiness with others?' 'He is now pleading his cause before you. Yes, I would gladly attempt such a work. I have seen your efforts and observed your success. The experiments which I have not witnessed you have always freely explained to me, with that gift of clearness which Vauvenargues called the "polish" of masters.[1] Initiated by affection, I would make myself initiator by admiration. It would be the history of a learned man by an ignorant one. My ignorance would save me from dwelling too strictly or too long on technical details. With the exposition of your doctrine I would mingle some fragments of your biography. I would pass from a discovery to an anecdote, and so arrange matters as to give the book not only the character of a familiar scientific conversation, which would hardly be more than the echo of what I have learnt while near you, but also to make it a reflex of your life.' 'You should postpone that until I am no longer here.' 'Why so? Why, before assigning to them their places, should we wait till those whose names will endure have disappeared from the scene? No; it is you, living, that I wish to paint--you, in full work, in the midst of your laboratory. And, in addition to all other considerations, I would add, that your presence in the flesh will be the guarantee of my exactitude.' _July 1883._ FOOTNOTE: [1] 'Vernis des maîtres.' CONTENTS. PAGE INTRODUCTION, BY PROFESSOR TYNDALL xi RECOLLECTIONS OF CHILDHOOD AND YOUTH--FIRST DISCOVERIES 1 FERMENTATION 40 ACETIC FERMENTATION-- THE MANUFACTURE OF VINEGAR 66 THE QUESTION OF SPONTANEOUS GENERATION 89 STUDIES ON WINE 112 THE SILKWORM-DISEASE 127 DECISIVE EXPERIMENTS 164 STUDIES ON BEER 168