INTRODUCTION 



SINCE the time when physiology first became an organised science 

 many volumes have been written on the digestive, excretory, nervous, 

 and other systems, but until recently no attempt has been made 

 to supply those interested in the reproductive processes with a 

 comprehensive treatise dealing with this branch of knowledge. 

 Indeed, in many text-books on physiology now commonly in use 

 either the section devoted to the reproductive organs is restricted to 

 a few final pages seldom free from error, or else the subject is entirely 

 omitted. Yet generative physiology forms the basis of gynaecological 

 science, and must ever bear a close relation to the study of animal 

 breeding. In writing the present volume, therefore, I have been 

 actuated by the desire to supply what appeared to me to be a real 

 deficiency ; and in doing so I have attempted, however inadequately, 

 to co-ordinate or give a connected account of various groups of 

 ascertained facts which hitherto had not been brought into relation. 

 For this purpose I have had occasion to refer to many books and 

 memoirs dealing with subjects that at first sight might have been 

 supposed to differ widely. Thus, works on zoology and anatomy, 

 obstetrics and gynaecology, physiology and agriculture, anthropology 

 and statistics, have been consulted for such observations and records 

 as seemed to have a bearing on the problems of reproduction. 



My sources of information are duly acknowledged in the footnotes, 

 but I am glad to take this opportunity of mentioning the following 

 works from which I have obtained special help : " The Evolution of 

 Sex," by Professors Geddes and Thomson ; " Obstetrics," by Professor 

 Whitridge Williams; the sections on the male and female reproductive 

 organs, by Professor Nagel and Dr. Sellheim, in Professor Nagel's 

 " Handbuch der Physiologic des Menschen " ; " Experimental Zoology," 

 by Professor T. H. Morgan ; and the writings of Mr. Walter Heape. 



The present volume is addressed primarily to the trained biologist, 

 but it is hoped that it may be of interest also to medical men engaged 

 in gynaecological practice, as well as to veterinarians and breeders of 



