... Theses de pleuritide

I.
Just as the location or the subject has given names to many other ailments, such as the nephritic disease of the kidneys, the colicky disease of the colon, hepatitis inflammation of the liver, and peripneumonia inflammation of the lungs, so also pleurisy pleuritis received its name from the affected location, derived from the word pleura side or rib.

II.
By its mention is understood the disease which the Latins call "lateral," or of the membrane enveloping the ribs, although most people very often call it by the name of the symptom, the pain of the side, improperly adapting the name of a symptom to the disease. Q. Serenus calls it a "dart," from the stinging pain which it inflicts in the manner of the point of some weapon. Others call it "pleurisy."

III.
When, however, there is a true and exquisite Pleurisy, it is the primary affection of the membrane surrounding the ribs, or certainly an inflammation of it and of the muscles continuous with it, as Galen attests in book 5, De locis affectis On Affected Parts, 2. It is manifest that neither that pain of the side which is caused by flatulence, nor the inflammation of the exterior muscles of the thorax, is to be called legitimate Pleurisy.

IV.
Furthermore, although true and legitimate Pleurisy can be referred both to increased magnitude and a broken unity, yet since the chief impediment is brought about by intemperance imbalance of humors and matter, it seems that it can be more correctly ascribed to a disease involving intemperance with matter.

V.
It has humors as its immediate cause, especially those which are hot and thin. For since the substance of the pleura is quite dense, it does not easily admit thick juices, such as those that are phlegmatic and melancholic. Therefore, with Galen as the authority, pleurisy is usually produced either from bile or from blood.

VI.
And although it can also be generated at times from a phlegmatic and melancholic humor, this happens very rarely during the initial stages, but more often when those are generated from the transmutation of other, hotter humors: after the thinner parts are digested first, and the thicker ones are left behind in the affected place, it is usually produced.