4 PHYSIOLOGY OF THE FUNGI 



principles are the aim, or as a study closely integrated with the fields of 

 science concerned with more practical problems. Often, the most 

 \aluablc results are obtained when research is not restricted by the 

 boundaries of practical application. 



AIMS 



This book is a discussion of living fungi, of their life processes and the 

 factors which influence them. It is written primarily for the student who 

 is acquainted with the structure of fungi and who is beginning the study 

 of their activities. From the discussions which follow the student should 

 gain a knowledge and understanding of the basic principles of fungus 

 physiology. To this end a considerable amount of factual material con- 

 cerning the behavior of specific fungi under specific conditions is cited. 

 The secondary aim of this book is to present a limited number of selected 

 references which may be of use to the student or investigator who wishes 

 more detailed information. Where possible, review articles have been 

 included. Complete documentation is impossible because of the tre- 

 mendous volume of literature. However, becoming familiar with the 

 literature is an essential part of a student's education. 



SCOPE 



As a text this book must cover many phases of the subject. One of the 

 first problems to be considered is the choice and preparation of suitable 

 media for growth and sporulation of the fungi under study. Since there 

 is no universal medium suitable for all fungi, a wise choice of media for 

 the purpose at hand is of fundamental importance in any investigation. 



Before a fungus can be studied in any great detail in the laboratory, it 

 is necessary to determine the conditions which affect growth. Growth is 

 a complex phenomenon, and some discussion of the phenomenon itself 

 and the ways of measuring growth is necessary for the understanding of 

 these conditions. Nutritional factors, such as source of nitrogen, source 

 of carbon, the presence of essential elements and vitamins, and the pH of 

 the substrate, afTect growth in interrelated ways. Each of these factors 

 and its importance in growth and other activities of fungi are discussed at 

 some length. 



The life processes of the fungi involve numerous chemical transforma- 

 tions. Living organisms make and use special organic catalysts, enzymes, 

 which control these reactions. The actions of the enzymes in the living 

 organism are coordinated and interrelated. A knowledge of the princi- 

 ples of enzyme action is essential to the study of fungus physiology. 



The fungi are able to make a far greater contribution to the production 

 of food and many other valuable products than they do at present. Both 



