PREFACE 



When the science of physiology was first introduced into 

 schools the texts offered for study treated largely of anat- 

 omy. As the subject developed and expanded it was 

 recognized that the study of anatomy should be made sub- 

 ordinate to that of function, and the text-books came to give 

 to function a place predominant over structure. Further ex- 

 perience emphasized the fact that the primary utility of the 

 study of physiology in schools consists in its bearing upon 

 health, and matters of personal hygiene came to occupy a 

 more and more prominent place. Still more recently problems 

 of public hygiene and general health have forced them- 

 selves to the front, and have been demonstrated to be an 

 important part of a person's education. With this broad- 

 ening scope and all these new aspects of life and health to 

 be considered, many phases of the subject of physiology 

 proper, themselves of scientific interest and importance, 

 have inevitably been given less and less attention^ while the 

 more practical topics have been accorded fitting' precedence. 



Although perhaps no two teachers would agree as to the 

 relative importance of any specific topic, certain it is, how- 

 ever, that without some knowledge of anatomy, physiological 

 facts seem isolated and without foundation; while rules bear- 

 ing on hygiene, taken alone, are learned by the student mere- 

 ly as barren rules without any persuasive reason for them. 

 In this book the emphasis placed upon different subjects is 

 that which has seemed to the writers to be a close approxi- 

 mation to their relative importance in the present state 

 of the sciences of physiology and hygiene. 



This book has one new feature which the authors feel 



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