PREFACE TO THE NINTH (REVISED) EDITION 



IN making this revision I attempted to preserve, so far as possi- 

 ble, the spirit and method of the Author. Numerous changes were 

 necessary, however, as well as the addition of much new material, 

 because of the great advances in Physiological knowledge during 

 recent years. 



One important departure was made from the former plan of the 

 book in emphasizing the adaptive character of human activities ; a 

 departure which required an entirely different treatment of the 

 Nervous System, as well as minor alterations throughout the book. 

 It involved likewise a rearrangement of the chapters so as to bring 

 together those dealing with Muscles, Nerves, and Sense-organs. 

 The conception of the Body as an Adaptive Mechanism is so help- 

 ful to an understanding of its activities, particularly on the part of 

 general students, that I felt justified in introducing it even at the 

 cost of very considerable departures from the original plan. 



To make room for the new material without enlarging the vol- 

 ume unduly some of the purely anatomical portions were con- 

 densed ; I hope without impairing their value seriously. Likewise 

 about forty illustrations were omitted, where they could be spared. 



For the few new figures introduced, electrotypes were furnished 

 by the publishers of HowelPs and Kirke's text-books of Physiology, 

 and of Bailey's and Scymonowicz and MacCallum's text-books of 

 Histology. 



E. G. M. 



BOSTON, April, 1910 



