INTRODUCTION 5 



which these bring that man owes his pre-eminent position 

 among all hving beings. The problem before us is to 

 show the bodily mechanisms by which man triumphs over 

 his environment. 



The study of function in the higher animals will there- 

 fore have to be considered from three aspects : — 



1. The mechanism possessed inherently by each organ, 



e.g. the mechanism of the heart-beat. 



2. The co-ordination of different mechanisms into bodily 



functions, e.g. the co-ordination of heart, lungs and 

 brain in the supply of oxygen to the tissues during 

 exercise. 



3. The protective reactions of the body to changes in 



its environment. 



In the following pages we shall try to develop the study 

 of function from this threefold point of view. 



