PREFACE 



Important advances in our knowledge of the structure and 

 physiology of cilia have been made since Gray's classical mono- 

 graph on Ciliary Movement was published in 1928. In particular, 

 the improvement of techniques of electron microscopy in the 

 last decade gave rise to a renewed interest in the structure of 

 cilia which has been rewarded with the discovery of a widespread 

 and consistent fibril pattern in all true cilia, flagella and sperm 

 tails. A parallel growth of interest in the physiology of the 

 beating and co-ordination of cilia has been taking place in these 

 years, and has been given an added stimulus by the success of 

 morphological studies. The primary purpose of this book is to 

 review advances in these fields since 1928, for in these 34 years 

 no attempt has been made to summarize fundamental work on 

 cilia and flagella in a comprehensive way. A review by J. A. 

 Rivera entitled Cilia, Ciliated Epithelium and Ciliary Activity 

 was published while the present book was in the press; Rivera 

 approached the subject in an entirely different way in summarizing 

 the effects of various agents on ciliary activity from the point of 

 view of the human physiologist, so that the two reviews scarcely 

 overlap at all. In the present book modern ideas on structure are 

 linked with modern ideas on physiology in an attempt to make a 

 single coherent story. 



The field of study has been divided into four parts: ciliary 

 structure, the effects of various agents on ciliary activity, the 

 physiology of beating of cilia and the physiology of co-ordination. 

 The second of these is intended for reference and for the intro- 

 duction of evidence used in the third and fourth parts. Summaries 

 of the material included will be found at the beginning of Chapter 

 II (structure of a typical cilium) and at the ends of Chapters IV 

 (beating activity) and V (co-ordination). 



The literature contains many thousands of references to 

 ciliary structure and functioning, and, in order not to overload 

 the book with bibliography, some selection had to be made. Only 



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