STUDIES ON FERMENTATION STUDIES ON FERMENTATION THE DISEASES OF BEER THEIR CAUSES, AND THE MEANS OF PREVENTING THEM BY LOUIS PASTEUR MEMBER OF INSTITUTE OF FRANCE, THE ROYAL SOCIETY OF LONDON, ETC. _A TRANSLATION, MADE WITH THE AUTHOR’S SANCTION, OF “ÉTUDES SUR LA BIÈRE,” WITH NOTES, INDEX, AND ORIGINAL ILLUSTRATIONS_ BY FRANK FAULKNER AUTHOR OF “THE ART OF BREWING,” ETC. AND D. CONSTABLE ROBB, B.A. LATE SCHOLAR OF WORCESTER COLL., OXFORD London MACMILLAN & CO 1879 PARDON AND SONS, PRINTERS, PATERNOSTER ROW, LONDON. TO THE MEMORY OF MY FATHER, FORMERLY A SOLDIER UNDER THE FIRST EMPIRE, AND KNIGHT OF THE LEGION OF HONOUR. THE LONGER I LIVE, THE BETTER DO I UNDERSTAND THE KINDNESS OF THY HEART AND THE EXCELLENCE OF THY MIND. TO THY EXAMPLE AND COUNSELS DO I OWE THE EFFORTS THAT HAVE BEEN DEVOTED TO THESE STUDIES, AS WELL AS TO ALL THE WORK I HAVE EVER DONE. AND NOW, HOW CAN I BETTER HONOUR THESE FILIAL REMEMBRANCES THAN BY DEDICATING MY BOOK TO THY MEMORY? L. PASTEUR. AUTHOR’S PREFACE. Our misfortunes inspired me with the idea of these researches. I undertook them immediately after the war of 1870, and have since continued them without interruption, with the determination of perfecting them, and thereby benefiting a branch of industry wherein we are undoubtedly surpassed by Germany. I am convinced that I have found a precise, practical solution of the arduous problem which I proposed to myself—that of a process of manufacture, independent of season and locality, which should obviate the necessity of having recourse to the costly methods of cooling employed in existing processes, and at the same time secure the preservation of its products for any length of time. These new studies are based on the same principles which guided me in my researches on wine, vinegar, and the silkworm disease—principles, the applications of which are practically unlimited. The etiology of contagious diseases may, perhaps, receive from them an unexpected light.