A clergyman measured blood pressure for the first time, using a horse

In 1733, Stephen Hales tied down a horse, inserted a brass pipe into its artery, and connected it to a nine-foot vertical glass tube. Blood shot upward and pulsed visibly with every heartbeat — the first direct measurement of blood pressure ever recorded. He published the results in Statical Essays: Haemastaticks, more than a century before anyone tried it on a person.

— Stephen Hales, Statical Essays: Containing Haemastaticks — 1733