viii PREFACE 



to the following for help in revising the proofs, for supplying me 

 with important references, or for assistance in other ways : — Professor 

 J. T. "Wilson, of Cambridge ; Professor C. G. Seligman, of London ; 

 Dr. W. Blair Bell, of Liverpool; Mr. H. M. Fox, of Gonville and 

 Caius College; Dr. A. C. Haddon, of Christ's College; Mr. K. J. J. 

 Mackenzie, of Christ's College; Mr. L. F. Messel, of Magdalene 

 College ; Mr. M. S. Pease, of Trinity College ; Dr. E. R Eastall, of 

 Christ's College ; Mr. H. G. Sanders, of St. John's College ; Mr. J. T. 

 Saunders, of Christ's College ; Dr. J. M. Duncan Scott, of Edinburgh ; 

 and Mr. E. Weatherall, of Christ's College. To Mr. Alan S. Parkes, 

 of Christ's College, I am under a special obligation for the great 

 trouble he has taken in preparing the indices and reading the final 

 proof sheets. » 



I wish further to express my gratitude to Messrs. Longmans, 

 Green, & Co. for having met my wishes in all possible respects in 

 matters connected with publication. 



The introduction to the first edition is reprinted as it originally 

 stood, except for a few necessary corrections. 



It is now more than twenty-two years since, in association with 

 Professor Cossar Ewart and Professor (now Sir Edward) Sharpey 

 Schafer at Edinburgh, I began the series of investigations on the 

 oestrous cycle from which the present work has grown, and I take 

 this further opportunity of thanking all who helped me in those 

 early days. Particularly I must mention Lord Carmichael of Skirling, 

 without whose generosity it would, in the absence of a regular 

 endowment, have been impossible to have conducted researches on 

 so extensive a scale. Since 1908 the work has been continued at 

 Cambridge, and I wish also to thank my colleagues in the schools 

 of Agriculture and Physiology, as well as the Master and Fellows of 

 my own college, for all they have done to make that work possible, 

 and for their never-failing encouragement during the past fourteen 

 years. 



F. H. A. MAESHALL. 



Ohkist's College, Cambridge, 

 Aucfiist 1922. 



