Saw this in the menu at the Everleigh last night and tried taking a photo but alas it was too dark, so here is the quote in good old plain text:
Bartending is an old and honorable trade. It is not a profession and I have no sympathy with those who try to make it anything but what it was. The idea of calling a bartender a professor or mixologist is nonsense.
Patrick Gavin Duffy – The Official Mixer’s Manual – 1934