D PREFACE 



scientific enough to be clear and logical, and to appeal to 

 reason, not a mere compilation of facts to be learned by rote. 

 To make it preparatory to a higher course in physiology 

 would be manifestly a mistake, for it would necessitate a 

 much more scientific plan of arrangement, and the introduc- 

 tion of an amount of material which would be confusing. 

 The teaching of anatomy and physiology in schools should be 

 considered chiefly as an aid in teaching hygiene, so that the 

 student may learn how to live a healthful life. 



The writer desires to acknowledge his indebtedness to R. M. 

 Wyckoff, M.D., for valuable aid in the preparation of the 

 manuscript for the press; and to R. Cresson Stiles, M.D., a 

 skillful microscopist and physician, for the chapter "On the 

 Use of the Microscope in the Study of Physiology." 



