PREFACE ix 



presented about this than about any of the other substances. However, 

 this should not be construed as desire on the author's part to emphasize 

 this substance. 



The subject of antagonistic effects of microorganisms has been re- 

 viewed in both general treatises (83, 229) and special papers (134, 166, 

 251, 256, 354, 355, 539, 540, 584, 616, 796, 799, 800, 838) ; special at- 

 tention has been paid to the occurrence of such organisms in the soil 

 (620, 794). Advantage was taken of these reviews in the preparation of 

 the comprehensive bibliography presented at the end of this mono- 

 graph. Attention is directed also to a recent complete review of the lit- 

 erature on the nature and formation of penicillin, the historical develop- 

 ment of our knowledge of this agent, method of assaying, and clinical 

 application (678). 



The author expresses his sincere appreciation to the members of the 

 staff of the Microbiology Department, New Jersey Agricultural Ex- 

 periment Station j to members of the Department of Research and De- 

 velopment of Merck & Co. and of the Merck Institute for permission 

 to use reproductions of their work j to Dr. G. A. Harrop of E. R, Squibb 

 & Sons for supplying the photograph of the penicillin-sodium crystals 

 used as the frontispiece to this volume j to Mrs. Herminie B. Kitchen 

 for her careful editing of the manuscript j and to the many investigators 

 in the field whose work has been freely cited both in the form of text or 

 tabular matter and as illustrative material. 



S. A. W. 

 November 75, 1944 



