James Jurin (baptised 15 December 1684 – 29 March 1750) was an English scientist and physician, particularly remembered for his early work in capillary action and in the epidemiology of smallpox vaccination.

[3] Jurin returned to Cambridge in 1715 to study medicine, becoming MD the following year and establishing a successful practice in London and Tunbridge Wells.

He studied mortality statistics for London for the fourteen years prior to 1723 and concluded that one fourteenth of the population had died from smallpox, up to 40 percent during epidemics.

[3] Jurin claimed that he had given "plain Proof from Experience and Matters of Fact that the Small Pox procured by inoculation ... is far less Dangerous than the same Distemper has been for many Years in the Natural Way.

Always advocating the Newtonian position, he was a keen controversialist, corresponding with Voltaire, Georges-Louis Leclerc, Comte de Buffon and Émilie du Châtelet.

He took an active part in defending Newton and attacking Gottfried Leibniz in the debate over vis viva,[3] opposing the views of Benjamin Robins and Pietro Antonio Michelotti.

He wrote an addendum (1738) On Distinct and Indistinct Vision to Robert Smith's Opticks and engaged in a lively epistollary exchange with Robins on the topic.

[3] With help from Edmond Halley and Roger Cotes, Jurin published a revised and translated Geographia Generalis, based on Newton's editions of the work.