

LIBRARY 



MASS. 



CONTENTS 



'AGE 



Preface ix 



5 



5 

 5 

 8 



to 



12 

 13 

 15 

 16 



22 



22 

 23 

 29 

 32 

 34 



36 



36 

 42 



5 Excretion and Water Balance 44 



1 . Excretion 44 



2. Water and salt balance 51 



6 Circulation and Respiration 53 



