PREFACE TO THE SECOND EDITION 



The scope of the book has been slightly altered to make it more in 

 accord with the Si/Uabus of Biophysics suggested by the General 

 Medical Council. Sections I. and II,, with the corresponding 

 exercises in Part II., cover the syllabus of the Physical Physiology 

 required by The Examining Board in England of the Royal College 

 of Physicians of London and the Royal College of Surgeons of Eng- 

 land. The text, however, has not been cut merely to suit examina- 

 tions, but an attempt has been made to view^ the human body as 

 far as possible as a physical machine. To do this adequately a 

 knowledge of mathematics beyond the stage usually professed by 

 medical and other students of the Biological Sciences is necessary. 

 Wc ha\'e therefore cut down mathematical treatment to the 

 mininunii and have indicated where the student who desires to 

 study the subject further inay get additional information. 



In spite of efforts to keep the book reasonably small, expansion 

 has taken place. A new chapter on Emulsions and Soaps has been 

 added, and the chapters on Surface Tension, General Receptors, 

 Eye, Ear, Voice and Movements of the Limbs have been almost 

 entirely rewritten. The greatest changes have been made in 

 Part II., as the result of six years' teaching experience. 



The main purpose of this preface is to record my thanks to all 

 who have helped me in the revision. My Staff at the College of 

 Medicine has generously come to my aid. Messrs. Seeker and 

 Saunders have read all the proofs and made many valuable sug- 

 gestions. Mr. Saunders and my wife have checked most of the 

 calculations. I am also indebted to my wife for much help in that 

 most tiring of tasks, the compilation of the index of subjects. 



Illustrations have been drawn from various sources, and I desire 

 to thank the various authors who have given me permission to 

 use their blocks. Especial mention should be made of the permis- 

 sion freely given by Professor L. J. Henderson to use his " Align- 

 ment Chart," and by Professor Leathes for his series of " Myelin " 

 ligures. 



Figs. 61, 75, 80, 81, 99 and 100 are from the late Professor 

 Starling's Principles of Human Physiology ; 2, 21, 2-t and 25 from 

 Pryde's Recent Advances in Biochemistry ; 68 and 88 from Lo\-att 

 Evans' Recent Advances in Physiology ; 72 from (ioulden's Rcfrac- 



