CONTENTS xiii 



II. The Mouth Cavity and its Functions . . 84 



III. (Optional.) The Throat Cavity and Gullet 



and their Functions 



IV. The Stomach and its Functions 

 V. The Small Intestine and its Functions 



VI. (Optional.) The Large Intestine and its Func- 

 tions 



VII. Absorption from the Alimentary Canal . 

 VIII. (Optional.) The Liver and its Functions 

 IX. Hygiene of Digestion 



VI. ClHCULATION or THE NuTKIENTS . 



I. Composition of the Blood 



II. Circulation and its Organs 



III. The Heart 



IV. The Blood Vessels . 



V. Circulation of the Blood . 



VI. Hygiene of the Circulation 



92 

 93 

 97 



98 

 101 

 102 



107 

 107 

 108 

 109 

 112 

 117 

 119 



VII. Kkspiration and the Production of Energy in 



Man .122 



I. Necessity for Respiration 122 



II. Adaptations for securing Oxygen and for ex- 

 creting Carbon Dioxid 124 



III. The Process of Breathing . . . .129 



IV. Hygiene of the Respiratory Organs . . . 132 



VIII. (Optional.) Additional Topics in Human Biology 139 



L The Skin 139 



IL The Skeleton 144 



IIL The Muscles 150 



IV. The Nervous System 154 



V. The Eyes . . " 162 



VI. The Ears 166 



IX. (Optional.) Great Biologists . •. . . .168 



