The authors recount personal experiments and contemporary research aimed at preventing illness through the new hygiene, combining firsthand trials of dietary regimes and mastication with summaries of physiological and bacteriological findings. Chapters examine digestion, food poisoning, protein debates, frequency and composition of meals, stimulants and meat consumption, breathing, exercise, bathing, cleanliness, and the cultivation of mental health; they describe institutional practices and public-health proposals, and conclude with practical household reforms and advocacy for health education. The tone is practical and programmatic, offering guidance grounded in early-twentieth-century scientific experiments and reform movements.