PREFACE 



This book is an attempt to describe as briefly as possible 

 how the body works. It is definitely addressed to those 

 who are already acquainted with the elements of the 

 subject, and is intended to supplement the larger text- 

 books. In writing it I have therefore omitted to describe 

 the physical and chemical processes upon which physiology 

 is so largely based, and I have assumed that the reader 

 is familiar with the experiments commonly performed in 

 the elementary class. For the same reason I have treated 

 histology only incidentally, and have not described 

 systematically the general structure of the central nervous 

 system. 



I admit to a plagiarism from Foster in the opening 

 words. I know no. better way of introducmg the subject. 



I wish to offer my warmest thanks to Dr. Marshall, 

 Mr. Barcroft, Dr. Hele, Dr. Hartridge and Dr. Peters for 

 their khidness in lookmg over different parts of the 

 manuscript and proofs and for their many helpful sugges- 

 tions. I am indebted, too, to Professor Hopkins for his 

 advice upon numerous points in Biochemistry. 



I wish to thank Prof. Langley (editor of the Journal of 

 Physiology), Prof. Schafer, Prof. Starling, Prof. Keith, 

 Prof. Sherrington, Dr. Marshall and Mr. Barcroft for 

 kindly allowing me the use of figures. 



My thanks are due to my wife for helping me with the 

 index. 



Ff. Roberts. 



Cainhriflqe, 

 October 1920. 



