Acknowledgements 



I WISH to acknowledge with gratitude the assistance given to nic in the 

 production of this book by the Editors of the Joiinml of Hygiene, the 

 Journal of General Microbiolo^^y, the Journal of Patliolo(^y and Bacteriolojiy, 

 Experimental Cell Research, and Biocliiniica et Biopliysica Acta, all ot whom lent 

 blocks of illustrations ; by the Camhridq^e University Press, Oliver & Boyd Ltd., 

 and the Elsevier Press who provided the blocks in question, and especially by 

 Dr. Emmy Klieneberger-Nobel, Dr. Woutera van Iterson, Professor J. 

 Tomcsik, Dr. A. L. Houwink and Drs. Birch-Anderson, Maaloe and Sjostrand, 

 whose admirable micrographs are the subject of many of these illustrations. 



I wish also to thank the Editors o( the Proceedings of the Royal Society, the 

 Journal of Bacteriology, the Annales de I'Institut Pasteur, the Proceedings of tlie 

 Society for Experimental Biology and Medicine and Cold Spring Harbor Symposia, 

 Professor R. H. Stoughton, Professor R. J. V. Pulvertaft, Dr. J. Lederberg, 

 Dr. R. R. Mellon, Dr. E. O. Morris, Professor A. R. Prevot and Drs. Chapman 

 and Hillier for permission to reproduce illustrations, and Dr. Joyce Grace, 

 Miss P. E. Pease, Miss B. G. Fewins and Mr A. A. Tuffery for their helpful 

 observations and material. 



Lastly, I wish to thank Professor J. F. D. Shrewsbury tor the facilities 

 which he has placed at my disposal ; and Miss C. M. F. Hale for her skilled 

 and patient work in the preparation ot the cytological material upon which 

 this monograph is based. 



K. A. BISSET, 



Department of Bacteriology, 

 University of Birmingham. 



