PREFACE TO SIXTH EDITION 



The continued demand for the Text-Book of Physiology, which has 

 led to the preparation of a Sixth Edition, has enabled the author to once 

 again revise and elaborate paragraphs and sections, to eliminate others, 

 and to insert such new material as seemed of value from the medical 

 point of view. In addition to the topics inserted and revised in the recent 

 Fifth Edition, viz. : the electric currents of the heart and their graphic regis- 

 tration; animal heat; internal secretion; the autonomic nerve system, etc., 

 revisions and additions have been made in the present edition to the 

 paragraphs relating to the mechanisms by which changes in the arterial 

 pressure are brought about; to the mechanism of carbohydrate metab- 

 olism; to physiologic actions of the spinal cord and spinal nerves. Other 

 revisions are also to be found in many sections of the text. Several new 

 diagrams illustrating the physiologic actions of cranial nerves have been 

 inserted. 



With these changes and additions it is hoped that this edition will meet 

 to a still further degree the needs of those for whom it is primarily intended, 

 viz. the medical student and the general practitioner. 



To those teachers and students who have recommended and used this 

 work and to whom I am indebted for generous praise, kind criticisms, and 

 helpful suggestions, I wish to express my sincere thanks and trust that in 

 its improved form it will continue to meet their approval. 



Once again I desire to express my appreciation of the unwearied and 

 invaluable assistance of Mr. I. A. Hagy in preparing the manuscript for 

 the press. 



To Messrs. P. Blakiston's Son & Co. I am greatly indebted for their 

 encouragement and generosity in the promotion of everything that per- 

 tains to the material value of this work. 



A. P. B. 



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