Cassii iatrosophistae naturales et medicinales quaestiones LXXXIIII, circa hominis naturam & morbos aliquot

XII. Why does the heat of coals generally generate a headache, but the heat of wood does not? Because the intense heat of coals densifies with its own heat; but the heat of wood has a certain humidity joined to it, which is indicated by the smoke itself. For smoke is a sign of the moisture contained in the wood. However, one should extinguish coals with a little wine, so that the usual harm does not follow them.

XIII. Why do pterygia wing-shaped membranes or growths on the eye abound in those working around the sea? For they happen in others as well, but especially in those who labor on the sea. It must be said that there are two kinds of pterygia: one, when the natural flesh located in the corner of the eye is overly extended or grows; the other, when a thin membrane extended over the circumference of the eye becomes calloused and swells. This membrane is difficult to discern in humans, but in certain other animals, and especially in lambs, it is seen most clearly by its thickness, which is not the case in man. This, therefore, is eroded by marine vapors on account of their acrimony, and it suffers callosity with inflammation, so that the densified place becomes a pterygium.