PREFACE 



In this the tenth American edition of the Handbook of Physiology 

 revisions and amplifications have been made throughout the entire text. 

 New subject matter, new illustrations, and the more recent refinements of 

 methods have been freely incorporated. This has unavoidably increased 

 the size of the volume. The chapters on Circulation, Respiration, Internal 

 Secretion, Metabolism and the Autonomic division of the Nervous System 

 in particular have been entirely rewritten and reillustrated. 



The chapter on the Circulation has been made to include the newer 

 researches on the development of cardiac physiology as regards rhythm 

 production, the control and finer adjustments of rate, and the conduction 

 phenomena that determine sequence. These factors, represented in the 

 highly differentiated bundle branch system, are given new emphasis and 

 new illustration. Physiological interest in Respiration has been inten- 

 sified by the practical problems of air navigation and by the newer inves- 

 tigations in the field of oxygen supply and oxygen control in relation to the 

 daily physiological round in both health and disease. The result has 

 been a new impetus to respiratory physiology contributed to by numerous 

 writers of the last decade. The works of Barcroft, Henderson, Schneider, 

 Greene and Gilbert and numerous others have been drawn on from this 

 field. 



The science of nutrition has made rapid advances. That subject has 

 been revised to call attention to the very fundamental work of Osborne 

 and Mendel on food factors necessary for growth; of Funk, Voegtlin and 

 others on the vitamines and nutritional diseases; of Lusk and DuBois in 

 the field of basal metabolism; of Van Slyke, Stadie, Harrop, and others 

 on blood gases, and of Banting, Best and Macleod on glycemia and the 

 hormone of the pancreas controlling sugar metabolism. 



The giant strides of the science of physiology make it difficult for a 

 textbook to keep pace with the literature, but it is hoped that the newest 

 facts and principles have been incorporated in so far as the limitations 

 of the available space permit. Many of the illustrative laboratory experi- 

 ments have been again rewritten," and improvements simplifying the 

 experimental technique have been incorporated. It is felt that the student 

 in Physiology gains the greatest strength in laboratory experience when 

 the tests he executes are chosen from the standpoint of the efficiency of the 

 entire work. In this field, under the present day conditions, the deter- 



