PREFACE TO THE SECOND EDITION 



Molds, Yeasts, and Actinomycetes by Henrici, published in 1930, 

 has been out of date for a number of years. The late author made 

 a start on a revision but had to abandon the task because of failing 

 health. We undertook the revision very largely out of respect and 

 regard for Dr. Henrici. We were aided by beginnings of a revision, 

 which, however, were entirely concerned with the first three chapters. 

 Chapter II was prepared by Henrici and is inserted almost ex- 

 actly as he wrote it. However, scattered notes in his personal marked 

 copy and especially the memory of many conversations indicated 

 the general nature of the revision which he hoped to make. 



Mere verbal changes, a modernization of nomenclature, a few 

 deletions and insertions of new material were found insufficient. A 

 complete rcAvriting was essential, and a considerable change in ar- 

 rangement of topics seemed advisable. Two entirely new chapters 

 dealing with material scarcely mentioned in the first edition have 

 been added. Some deletions of portions of the old book, which ex- 

 perience had shown were of limited value, were made. In spite of 

 all this, however, we have attempted to produce a book in the spirit 

 of the original book — namely a 'discussion of molds, yeasts, and 

 actinomycetes for students of bacteriology. Like Henrici, we in- 

 clude in the term students many individuals who have completed 

 their formal education. It was for such students that Henrici called 

 his first edition a handbook. 



Dr. Henrici was very insistent that, for their own good, bacteriol- 

 ogists would do well to have some working knowledge of mycology. 

 Inasmuch as most books on fungi are written for the botanist, the 

 agriculturist, the phytopathologist, and others, the emphasis, in gen- 

 eral, is often on those forms of least interest to the bacteriologist, 

 and the forms of greatest interest to him are likely to be ignored or 

 merely mentioned. Here the emphasis is reversed. The stress on 

 medical and industrial applications of mycology has been retained 

 in this edition and has been intensified. Moreover, Henrici was 

 of the opinion that bacteriologists, whatever their special field, should 

 have some knowledge of the morphology of fungi— classification, 

 cytology, genetics, life cycles, and so on— so that they might better 



