William Harvey lost most of his patients and was generally ridiculed for his theory that blood did not oscillate back and forth in the vessels of the body, as the great Greek physician Galen claimed, but moved in one direction, in a closed curve. It circulated, Harvey claimed, and was promptly dubbed the Circulator. The nickname was a nasty pun: "Circulator" was a slang Latin term used to describe a dodgy peddler who hawked medicines at the circus. Harvey, in other words, was a charlatan or quack.
[Harvey prevailed in the end. By the time of his death, the circulation of blood was generally accepted as a biological fact.]
[The Chinese Emperor Hwang Ti observed that "all the blood in the body is under the control of the heart... the blood current flows continuously in a circle and never stops." The date? 3650 BC.]