Dr.Maitland, who had been physician to the mission to the Porte, set up in practice and inoculated under her patronage.

The "heathen rite" was vigorously preached against by the clergy and was violently abused by the medical faculty.

Undismayed by the powerful opposition, however, she persevered in season and out, until her efforts were crowned with success.

She was fortunate in enlisting the co-operation of that distinguished doctor, Richard Mead, celebrated by Pope in his "Epistle to Bolingbroke," "I'll do what Mead and Cheselden advise." Mead, in 1720, when an epidemic of the plague was feared in London, published a treatise: "A Short Discourse concerning Pestilential Contagion and the Methods to be used to Prevent it." It was reprinted seven times within a year, and an eighth edition appeased in 1722.

Lady Mary obtained permission, in 1721, to experiment on seven condemned criminals.