I . Habit and Instinct I T is important to distinguish between instinctive or innate activities of mind and body and those activities that are acquired in the school of experience. Human life as we know it today has evolved from an ancient ancestry. That mankind has survived the trials and tribulations of a long history is testimony to the human powers of adaptation. Conforming to the rigorous demands of a hostile environment and meeting the day-to-day challenge of danger, disease and famine, mankind relied on innate, inborn reserves of strength and resourcefulness. Survival depended, and still depends, on man's native instinct to act spontaneously to preserve the species in times of danger and uncertainty.