394 .HUMAN PHYSIOLOGY 



physiology. We have touched upon one of its aspects in 

 speaking of ventilation. Its larger problems draw our 

 attention from the individual, who is central in physi- 

 ology, to the contact of human beings in communities. 

 This is the subject matter of works on Public Health. 



It is most desirable that the reader who comes to the 

 end of an account such as has been attempted here, 

 dealing with the body living by itself, pass on to learn 

 something of preventive medicine. He will find the 

 story one of absorbing interest, rich in personalities and 

 courageous achievement. He will come to realize how 

 the relative security of life in our time stands contrasted 

 with its uncertainty in all earlier ages and how bright 

 are the promises for the future. 



