[1] An expert in yellow fever, he helped discover its epidemiology, improved city sanitation, and authored the federal Quarantine Act of 1799.

Bayley was born in 1745 in Fairfield, then in the Colony of Connecticut, to a family of French Huguenot and English descent, based in New Rochelle, New York.

1768, m. 1790 to Wright Post, d. April 9, 1856), Elizabeth Ann (1774-1821, later known as Mother Seton, and the first native-born citizen of the United States to be declared a saint[1]), and Catherine (1776–8).

[4] A Loyalist, Bayley returned to America and enlisted in the British army as a surgeon at the start of the American Revolution and was stationed in Newport, Rhode Island.

Three daughters and four sons were born of this marriage: Richard, Andrew Barclay, Charlotte Amelia, William, Mary Fitch, Guy Carleton (b.

[7] His laboratory was attacked in the 1788 Doctors' Riot, which was sparked by public outrage at the illegal procurement of corpses for dissection.

As a result, around 1796, he was appointed as the first health officer of the Port of New York, in charge of a quarantine station in what is now Tompkinsville, Staten Island.