PREFACE. 



My object throughout this manual has been to condense the 

 information as much as possible, for which purpose I have 

 omitted all special reference to the physiology of the dog, 

 and have not touched upon the histology of the tissues, or 

 methods of physiological inquiry. 



The reasons for these omissions are obvious : special 

 canine physiology is of subordinate interest to the pro- 

 fession, and our information about this animal is so com- 

 plete, that no difficulty is experienced in obtaining it, when 

 required, from human text-books. The histology of the 

 tissues is already before the profession, and methods of 

 physiological inquiry are only needed for laboratory work, 

 for which purpose this book is not intended. 



In the description of the physiology of the various organs 

 and tissues, the horse is necessarily taken as the type ; but 

 the ox, sheep, and pig are dealt with wherever their special 

 physiology requires it. 



It was my original intention to publish nothing until I 

 had gone over the field of equine physiology, but I found, 

 after several years of work, that the information I had 

 collected was a mere drop in the ocean, for inquiries of this 



