Importance of some Knowledge of the Body and its Needs—Fearful Responsibility of entering upon domestic Duties in Ignorance—The fundamental vital Principle—Cell-life—Wonders of the Microscope—Cell-multiplication—Constant interplay of Decay and Growth necessary to Life—The red and white Cells of the Blood—Secreting and converting Power—The nervous System—The Brain and the Nerves—Structural Arrangement and Functions—The ganglionic System—The nervous Fluid—Necessity of properly apportioned Exercise to Nerves of Sensation and of Motion—Evils of excessive or insufficient Exercise—Equal Development of the Whole 199 CHAPTER VIII. DOMESTIC EXERCISE. Connection of Muscles and Nerves—Microscopic cellular muscular Fibre—Its Mode of Action—Dependence on the Nerves of voluntary and involuntary Motion—How Exercise of Muscles quickens Circulation of the Blood, which maintains all the Processes of Life—Dependence of Equilibrium upon proper muscular Activity—Importance of securing Exercise that will interest the Mind 208 CHAPTER IX. HEALTHFUL FOOD AND DRINKS. Construction of the Body in Relation to Food—The Construction of a Kernel of Wheat as proportioned to the Body—Construction and Action of the Stomach—Advice as to Food, Drinks, and Stimulants—Opinions of Physicians 214 CHAPTER X. ON CLEANLINESS. Construction of the Skin—The secreting Organs—Care of the Skin 235 CHAPTER XI. CLOTHING. Construction of the Bones—Influence of Dress—Description of two Modes of Breathing, and the Effects of Weight and Tightness of Clothing—Proper Mode of sustaining the Clothing 243 CHAPTER XII. EARLY RISING. A Virtue peculiarly American and democratic—In aristocratic Countries, Labor considered degrading—The Hours of Sunlight generally devoted to Labor by the working Classes, and to Sleep by the indolent and wealthy—Sunlight necessary to Health and Growth, whether of Vegetables or Animals—Particularly needful for the Sick—Substitution of artificial Light and Heat by Night a great Waste of Money—Eight hours’ Sleep enough—Excessive Sleep debilitating—Early Rising necessary to a well-regulated Family, to the Amount of Work to be done to the Community, to Schools, and to all Classes in American Society 254 CHAPTER XIII. DOMESTIC MANNERS.