The literature concerning infection of the lung following operative procedures has increased much more rapidly since the bronchoscope has become a recognized instrument of diagnosis as well as of treatment.
Postoperative pneumonias such as those seen a decade or two ago are not frequently seen today, which may be due partly to increased knowledge and to improved technic in administering anesthetics, although to my mind this is not all.
The necessity of the respiratory tract to life was known in ancient times, for the first that one reads of man as a living creature relates to his breath: "And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life, and man became a living soul."
At what period in the development of medical knowledge was infection of the lung recognized as being derived from the upper respiratory tract? Aristotle (384-322