vi PREFACE 



laboratory practice, and had been asked to perform an "autopsy" 

 in order to arrive at an understanding of the structure and pos- 

 sible functioning of the victim, long dead and mummified, little 

 stimulation of thought or interest would have resulted. 



The further objection may be raised that knowledge of fungus 

 activities is still too meager to be presented in an organized man- 

 ner to students. All that need be said in rejoinder is that the 

 seven-league boots of physics, physical chemistry, biochemistry, 

 physiological chemistry, and colloid chemistry will enable the 

 teacher and the student alike to wade far out into the depths of 

 the vast mvcologic unknown. Beginnings must be made. 



Opinions have a limited value in the field of science. At times, 

 ours are expressed. .Mycologists may not find themselves in 

 accord with some of these opinions. Be that as it may, data will 

 some day exist upon which ultimate truth will become securely 

 established, and then, of course, opinions now expressed will lose 

 all value. 



Our efforts have been concentrated on helping the student to 

 understand fundamentals. We have chosen % to include data and 

 conclusions from certain reports of researches and have omitted, 

 without apparent reason for so doing, to mention others that are 

 equally good and pertinent. No intentional discredit or lack of 

 merit is implied in these omissions. In a volume of this scope it 

 is simply impossible to consider each subject monographically. 

 The relative importance of subjects is not reflected by the amount 

 of space devoted to them. References to reports are given at the 

 end of each chapter; these papers contain additional pertinent 

 references to other researches, so that interested persons can gain 

 a more comprehensive grasp of a particular subject. 



Most of the illustrations are adapted from those of others. If 

 in any instance the author of the original drawing or graph has 

 not been mentioned, the omission is unintentional. We herewith 

 acknowledge again, with gratitude, the kindness of those who 

 supplied us with certain illustrative materials, and of Mary H. 

 Wolf for her assistance in the preparation of illustrations. 



Since the legends are intended to explain the illustrations ade- 

 quately, mention of illustrations is omitted from the text. 



We are indebted also to Dr. L. E. Wehmeyer, who carefully 

 read the entire manuscript, for his criticisms and suggestions and 

 to Mrs. Fred T. Wolf for her help in reading proof and in the 



