XIX. THE STIFFENING RODS OF THE BODY-MACHINE 210 XX. OUR TELEPHONE EXCHANGE AND ITS CABLES 216 XXI. THE HYGIENE OF BONES, NERVES, AND MUSCLES 228 How to Get and Keep a Good Figure 228 Our Feet 230 Sleep and Rest 232 Disorders of Muscles and Bones 233 Troubles of the Nervous System 235 XXII. EXERCISE AND GROWTH 241 XXIII. THE LOOKOUT DEPARTMENT 252 The Nose 253 The Tongue 257 The Eye 259 The Ear 266 Our Spirit-Levels 269 XXIV. THE SPEECH ORGANS 271 XXV. THE TEETH, THE IVORY KEEPERS OF THE GATE 277 XXVI. INFECTIONS, AND HOW TO AVOID THEM 286 XXVII. ACCIDENTS AND EMERGENCIES 314 QUESTIONS AND EXERCISES 331 GLOSSARY AND INDEX 343 ILLUSTRATIONS PAGE TO ATTEMPT TO RUN AN AUTOMOBILE WITHOUT KNOWING HOW WOULD BE REGARDED AS FOOLHARDY 2 WHERE SUN-POWER IS MADE INTO FOOD FOR US 6 THE FOOD ROUTE IN THE DIGESTIVE SYSTEM 8 THE SALIVARY GLANDS 10 A SECTION OF THE LINING SURFACE OF THE STOMACH 14 A LONGITUDINAL SECTION OF STOMACH, OR PEPTIC, GLANDS 15 A CHEAP HOME-MADE ICE BOX 23 A BABY-MILK STATION 30 CLEAN, DRY SUNNING YARDS AT A MODEL DAIRY 33 CLEANLINESS BEFORE MILKING 34 THE MILKING HOUR AT A MODEL DAIRY 35 MILKING BY VACUUM PROCESS 36 WASHING THE BOTTLES AT A MODEL DAIRY 37 BACTERIA IN CLEAN AND IN DIRTY MILK 38 DANGER FROM DIPPED MILK 38 MILK INSPECTION AT THE RETAIL STORE 39 A THOROUGH BAKING, AND A VALUABLE CRUST 44