the French language. It is sincerely hoped, however, that the rendition of this book into the English language will in no way inhibit the study of the French language that language in which Pasteur, Bernard, Magendie, Berthelot, and others have published their classic investigations.
This English edition is based on Guilliermond's "Les Levures," which was published in 1912, appearing as a volume in the section on Cryptogamic Botany of Encyclopédie Scientifique. This series is edited under the direction of Doctor Toulouse. To merely translate a volume on a subject which is being developed as rapidly as the yeasts would be entirely inadequate. Consequently with the collaboration of Professor Guilliermond, the translator has added much new material which has been published since 1912. Without the assistance of Professor Guilliermond, this could not have been done as completely. The English edition may not, then, be regarded as a mere translation of the last French edition.
The rendition of a text from a foreign language into the English language is beset with difficulties which are most clearly appreciated by those who have performed similar pieces of work. In all cases a literal translation has not been attempted; however, the opinions of the original author have been given as closely as possible. It is trusted that this English edition will make it easier for students to pursue their study of these important microorganisms and for the practitioner to more easily solve the problems with which he has to cope. I owe many thanks to my colleagues, too numerous to mention here, for expression of their advice at various times and for their interest during the progress of the work.
FRED W. TANNER
UNIVERSITY OF ILLINOIS
URBANA, ILLINOIS
June, 1919
