FROM

THE AUTHOR'S PREFACE

TO THE GERMAN EDITION

In the course of a number of years, during which I had the honour to act as assistant to Prof. Emil Chr. Hansen at the Carlsberg Laboratory, and to assist him in the practical courses of instruction conducted there from time to time, the wish was frequently expressed by students to have at their disposal a handbook which would contain an adequate description of the fittings, apparatus and methods of a fermentation laboratory, as well as of the biology of the organisms of fermentation; in short, a guide by means of which the usual experiments of such a laboratory can be carried out. A similar request reaching me from the well-known publisher, Max Waag, of Stuttgart, I could but conclude that a real necessity existed for such a book.

The contents of the present work are divided into three sections. The first of these contains a description of the manner in which the science of the organisms of fermentation has gradually developed; at the same time, an indication is given of the most important steps which have marked the progress of our science.

The second section describes the fitting up of the laboratory and all that is necessary for conducting work. Laboratory methods are then explained, special attention being given to the preparation of pure yeast cultures in large quantities. Finally, the third section treats of the most important micro-organisms of the alcoholic fermentation industry. The book thus deals with that domain in which Hansen has opened up so many new paths.

For each section there is a bibliography which embraces the most important researches, and contains explanatory notes. The literature after 1st January, 1900, could not be included. In certain cases I have made experiments for the sake of confirmation, and have quoted some results not hitherto published.

The branch of the fermentation industries with which my book is chiefly concerned is that of brewing, which was the first to make use of Hansen's pure culture system, and hence to adopt a rational mode of working. Brewing has thus, to a certain extent, become the model for the other branches of the alcoholic fermentation industry. The science of the organisms of fermentation as set forth in this book deals, however, not only with practical applications, but also with important theoretical aspects of chemistry and botany. ALB. KLÖCKER.

COPENHAGEN, January 1900.

PREFACE TO THE ENGLISH TRANSLATION

BY PROFESSOR ADRIAN J. BROWN, M.Sc., F.I.C.

A VERY considerable and rapidly increasing amount of attention is now being given in this country to Technical Microbiology in its relation to the fermentation industries, and consequently there is a growing demand for sound textbooks on the study of the "fermentation organisms" for the use of students who are taking up this special branch of work. But it is continually being forced on the notice of the writer, whose work is intimately connected with the teaching of Microbiology, that this demand is very inadequately satisfied at present. Whilst we are almost too well supplied with textbooks on Bacteriology as related to the organisms of disease, the number of books in our own language dealing with the subject of "fermentation organisms" is very limited, and this is especially the case with works describing the more modern developments of experimental method connected with the study of these organisms.

For this reason the

publication of an English translation of Herr Klöcker's Gärungsorganismen, a work specially devoted to the treatment of laboratory methods employed in the study of "fermentation organisms," should be welcomed by all teachers and students of Technical Microbiology, for they have now placed in their hands a book which cannot fail to be of great assistance to them. The special merit of this book requires no recommendation here, for it is written by one who is a specialist in his subject, and whose name is well known, not only for his own valuable researches, but also as a distinguished assistant of the illustrious Dr. Emil C. Hansen, to whom every one connected with technical fermentation in this country and abroad is so deeply indebted. The translators of the work, Mr. J. H. Millar and Mr. G. E. Allan, have been most successful in the performance of their task, and we congratulate them on a volume which should be the laboratory companion of every student of Technical Microbiology in this country. We believe also that this book will be a useful addition to the library of the pathological bacteriologist. Pathological bacteriology, owing to its phenomenal growth, is inclined to forget its past history and lose all connection with the older branch of microbiology from which it originally sprang. We think it will be found that the development in method of experiment and research in connection with the study of "fermentation