CONTENTS. 



CHAPTER I. 



PAGE 



INTRODUCTION i 



Health. Care of the Body. Hygiene. Physiology. Organ. Func- 

 tion. Anatomy. Tissues. Cells. Physiological Division of Labor. 



CHAFfER II. 

 MOTION 7 



Motion Necessary to Life. Experiments with our Muscles. Action 

 of Muscle. Structure of Muscle. Connective Tissue. Laws of 

 Muscle Action. Flexors and Extensors. Symmetry. Muscles and 

 Bones. Levers. Locomotion. Uses of Bones. 



CHAPTER III. 



THE GENERAL FUNCTIONS OF THE NERVOUS SYSTEM SENSATION 



AND MOTION 24 



Muscles controlled by Nerves. Voluntary and Involuntary Motion. 

 The Spinal Cord. The Spinal Nerves. Structure of Nerves. 

 Function of Nerves. Structure of the Spinal Cord. Ganglions. 

 Reflex Action of the Spinal Cord. Reflex Action of the Spinal 

 Cord in the Frog. Function of the Nerve Roots. Importance of 

 Reflex Action. Inhibition. Nature of a Nervous Impulse. Har- 

 mony in Muscle Action. Nerves depend on Blood Supply. 



CHAPTER IV. 



CIRCULATION OF THE BLOOD 39 



The Blood and its Work. The Rate of the Heart Beat. Position 

 and Size of the Heart. The Valves of the Heart. The Blood 

 Tubes Connected with the Heart. The Action of the Heart. Work 

 and Rest of the Heart. Action of the Large Arteries. Variation 

 in Blood Supply. Plain Muscle Fibers in the Walls of the Arteries. 



vii 



