PREFACE 



MANY years of experience in teaching physiology * 

 have convinced me that the ideal of a text-book should 

 be the clearness, accuracy and simplicity obtained by 

 viewing the human body as a machine automatically ad- 

 justed to its work and its surroundings. From such a 

 viewpoint, its complex structure is resolved into the 

 definite working parts of a well-regulated mechanism ; its 

 varied forms of activity are revealed as organized effort 

 toward development, maintenance and adaptation to en- 

 vironment ; and the laws of its health are seen to be the 

 reasonable conditions essential to its effective working. 



Whenever possible, technical terms and names have 

 been omitted for the sake of relieving overburdened 

 memories and of leaving them receptive for the impor- 

 tant practical aspects of the subject. Indeed, the at- 

 tempt throughout has been to utilize and supplement 

 the knowledge of the student and thus to give to the 

 physiology, and especially to the hygiene, a working 

 value in his daily thought and life. When technical 

 terms have of necessity been used, they have been itali- 

 cized, not in every case where they first occur, but where 

 they are most fully explained. This method supple- 

 mented by an accurate index is believed to be preferable 

 to the very inadequate glossary often used. 



1 State Normal School, Oswego, N. Y. ; Cook Co. Normal School, 

 Illinois; Sargent Normal School of Physical Education, Cam- 

 bridge, Mass.; Harvard University, Cambridge, Mass. 



