This relic is a Revolutionary War era bleeding bowl.
In medical practice bleeding bowls were used to catch the blood released during bloodletting, a procedure once favoured by doctors and barber surgeons to treat a wide range of medical conditions. The appearance of the blood caught in the bowl was also a diagnostic tool for physicians, who examined it for clues about the body's internal state. Bloodletting, whether by a physician or by leeches, was based on an ancient system of medicine in which blood and other bodily fluids were regarded as "humours" that had to remain in proper balance to maintain health. With a history spanning at least 3000 years, bloodletting has only recently—in the late 19th century—been discredited as a treatment for most ailments.
This bowl is made of brass, is 10 1/4 inches in diameter and 2 1/2 inches high. Photo is provided by a private collector.