Everything Is Soothed By Oil, And This Is The Reason Why Divers Send
Out Small Quantities Of It From Their Mouths, Because It Smooths Every
Part Which Is Rough.
Everything is soothed by oil, and this is the reason why divers send
out small quantities of it from their mouths, because it smooths every
part which is rough.
-- Pliny the Elder (23-79 AD)
-- Natural History, Book ii, Sect. 234