Reply #4: One answer:

[Zookeeper]

http://www.answerbag.com/q_view/20527

To be precise, it was the lobe of his left ear which he put into an
envelope and gave to a brothel wench named Rachel with
these words: "Guard this object carefully." After he tried to
drink a quart of turpentine in his studio, he was sent to the
asylum at Saint-Remy on May 7, 1889. The doctors began to
treat him with hydrotherapy for acute mania and epilepsy. A
precise diagnosis of Van Gogh's illness is still unavailable,
despite hundreds of conjectures. We do know a few facts:
Van Gogh suffered from syphilis contracted from prostitutes
off the docks at Antwerp; there was also a history of mental
illness in his family. Some physicians now believe Van Gogh
may have had a congenital brain lesion that was aggravated by
absinthe.