Book 2
CHAPTER I. ON PNEUMONIA
1
ANIMALS live by two principal things, food and breath (spirit, pneuma); of these by far the most important is the respiration, for if it be stopped, the man will not endure long, but immediately dies. The organs of it are many, the commencement being the nostrils; the passage, the trachea; the containing vessel, the lungs; the protection and receptacle of the lungs, the thorax. But the other parts, indeed, minister only as instruments to the animal; but the lungs also contain the cause of attraction, for in the midst of them is seated a hot organ, the heart, which is the origin of life and respiration. It imparts to the lungs the desire of drawing in cold air, for it raises a heat in them; but it is the heart which attracts. If, therefore, the heart suffer primarily, death is not far off.
