The Philosophy of Health; Volume 2 (of 2)
 or, an exposition of the physical and mental constitution of man

by Southwood Smith

"The Philosophy of Health; Volume 2" by Southwood Smith is a scientific publication written in the mid-19th century. This work is a continuation of the exploration of human health, emphasizing the physical and mental constitution of individuals as a means to promote longevity and happiness. The book delves into various bodily functions, particularly focusing on respiration and its vital role in maintaining health. The opening of the second volume begins with a detailed examination of respiration, comparing its processes in both plants and animals. Smith discusses the apparatus involved in respiration, including the trachea, bronchi, and lungs, and outlines the mechanics of inspiration and expiration. He highlights the significance of air in sustaining life, noting that while organisms can survive without food for extended periods, they cannot endure without air. The intricacies of how respiration affects blood and air interactions are introduced, setting the stage for an in-depth scientific analysis of these essential biological functions throughout the volume.