Metrocles  

"The supposed story of Metrocles' conversion to Cynicism is reported by Diogenes Laërtius. Metrocles had apparently farted while practicing a speech, and became so upset that he shut himself up in his home, attempting to commit suicide by starving himself. Crates visited him and made him a dinner of lupines, explaining to him that what he had done was according to nature and therefore nothing to be ashamed of. When Crates himself farted to demonstrate how natural it was, Metrocles was persuaded to let go of his shame."--Sholem Stein

"Metrocles was the brother of Hipparchia; and though he had formerly been a pupil of Theophrastus, he had profited so little by his instructions, that once, thinking that, while listening to a lecture on philosophy, he had disgraced himself by his inattention, he fell into despondency, and shut himself up in his house, intending to starve himself to death. Accordingly, when Crates heard of it, he came to him, having been sent for; and eating a number of lupins, on purpose, he persuaded him by numbers of arguments, that he had done no harm; for that it was not to be expected that a man should not indulge his natural inclinations and habits; and he comforted him by showing him that he, in a similar case, would certainly have behaved in a similar manner. And after that, he became a pupil of Crates, and a man of great eminence as a philosopher."--Lives and Opinions of Eminent Philosophers (Charles Duke Yonge translation)