

PREFACE TO THE THIRD EDITION 



EVEN during the five years of war, which have elapsed since the appear- 

 ance of the last edition, physiology has continued to advance, and I have 

 had, in revising this work, to introduce a number of alterations, especially 

 in the latter half, in order to make the presentation of the material more 

 in accord with our actual knowledge. The chief changes affect the section 

 on Sense Organs, which has been revised and largely rewritten by Dr. H. 

 Hart ridge, who is entirely responsible for the Section on Vision, which 

 is quite new. The fifty pages increase in the size of the book is due entirely 

 to the more adequate treatment of this subject which I have secured 

 by Dr. Hartridge's co-operation, room having been found for the other 

 additions to the work by corresponding omissions. 



In the preparation of this edition I have received valuable aid from 

 my wife, who undertook not only the whole burden of proof correcting 

 but also the arrangement of the index. I am also much indebted to many 

 friends, known and unknown, who have pointed out mistakes and omissions 

 in previous editions. I shall be glad to receive any suggestions as to points 

 in which this text-book may be made more useful tq students. 



ERNEST H. STARLING. 



University College, London, 



March 1920. 



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