PREFACE 



The study of the salivary glands and their secretions enjoyed 

 greater popularity in the past than it does at the present time. 

 Indeed, however great the importance of saliva in the mastication 

 of food and maintenance of our health, the evidence for any unique 

 and essential role of these secretions in the body economy is not 

 great. In most courses of physiology, not even a single lecture is 

 devoted to saliva secretion. On the other hand, the salivary glands 

 are wonderful pieces of physiological machinery which provide 

 unexcelled preparations for the study of autonomic innervation, 

 the action of drugs, changes in blood flow and metabolism during 

 activity, as well as the processes involved in the transport of water 

 and electrolytes. A glance at the table of chapter headings will 

 show that these aspects of the glands have received a great deal of 

 space in this book, in direct relationship to the personal interest of 

 the authors in these matters. Nevertheless, most aspects of salivary 

 physiology have been covered, although not always exhaustively. 

 For instance, it was not considered desirable to refer to all of the 

 vast literature on the composition of the saliva ; rather, selections 

 have been made from the papers illustrative of the principles 

 governing saliva composition with neglect of those offering only 

 isolated and unrelated observations. Similarly, in the chapter on 

 comparative physiology, material is cited for the light it throws on 

 the modification of salivary function in different branches of the 

 animal kingdom, but the chapter is in no way encyclopaedic. 



We hope that we have laid at least as much emphasis on the 

 present state of ignorance of many aspects of salivary physiology 

 as upon the facts that are solidly established. The interested reader 

 should find many problems that are waiting to be worked upon. 

 We hope that the critical approach to some of these problems may 

 be of special value to workers in the field of dental research. 



The writing of this book was helped by the circumstance that 

 enabled one of us (N. G. E.) to spend several months in Montreal 

 as a visiting professor at McGill University in the fall of 1958. We 

 have also been aided in great measure by the library staffs « 



