PREFACE TO FIFTH EDITION 



In the preparation of the fifth edition of the Text-book of Physiology 

 the attempt has been made once again to increase its value to those for 

 whom it is primarily intended, viz., students of medicine and practitioners 

 who desire to keep in touch with the progress of physiology. With this 

 view the text has been subjected to careful revision and in many sections 

 entirely rewritten. Some of the anatomic diagrams have been eliminated 

 and physiologic diagrams inserted. The suggestions and criticisms con- 

 tained in reviews and book notices, in letters from teachers and practi- 

 tioners have been considered and in many instances adopted, with benefit 

 to the text, for all of which the writer expresses his appreciation. 



Among the subjects which have been added, enlarged or revised 

 may be mentioned the metabolism of the food principles; carbohydrate 

 metabolism; the electric currents of the heart and their graphic registra- 

 tion, the electro-cardiogram; animal heat; internal secretion; the localiza- 

 tion of functions in the cerebral cortex; the autonomic nerve system, etc. 

 These changes have necessitated the elimination of less important mate- 

 rial, but, nevertheless, some thirty-seven additional pages have been 

 added to the general body of the text. 



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. 



