CONTENTS 



CHAP. PAGE 



1. HOW THIS BOOK CAME TO BE WRITTEN. . I 



2. THE MUSCLES, WHICH ARE THE MOTOR ENGINES 



OF THE HUMAN BODY, COMPARED TO THE 

 ENGINE OF A MOTOR CYCLE. THE ENGINES 

 WHICH MOVE THE LEGS IN WALKING . 8 



3. HOW THE BACKBONE IS BALANCED AS WE SIT, 



STAND, OR WALK, AND SOME POINTS OF 

 DIFFERENCE BETWEEN THE MOTOR CYCLE 

 AND HUMAN BODY . . . . . 2 1 



4. ARE OUR MUSCLES REALLY INTERNAL-COM- 



BUSTION ENGINES ? . . . . . 28 



5. MUSCLES ACT AS RECIPROCAL ENGINES, BUT IT 



TAKES YEARS TO LEARN HOW TO MANAGE 



THEM . . . . . . . 39 



6.- THE BONES OF OUR BODY ARE LIVING LEVERS. 

 THE SKULL, BESIDES CONTAINING THE BRAIN, 

 SERVES AS A LEVER OF THE FIRST ORDER . 47 



7. THE FOOT AND THE FOREARM AS LEVERS . 57 



8. BONE-BUILDERS AND THE MANNER IN WHICH 



THEY CONSTRUCT LIVING LEVERS . . 69 



9. A PERFECT LUBRICATING SYSTEM 80 



IO. WHAT HARVEY WAS TAUGHT CONCERNING THE 



HEART . . . . . . . 89 



