October 1748: By Medicines & Attendance myself & Ice £7.19.11 By Lodging &c 7 weeks 6. 6. 7
From William Parks, on another occasion, he bought "Rattlesnake root," which was promoted in 18th-century Virginia as a specific against the gout, smallpox, and "Pleuritick and Peripneumonic Fevers."[112] Twice he bought "British oyl," a favorite popular nostrum sold in tall, square bottles, and on another occasion "2 bottles of Daffy's Elixir."[113] In 1749 he settled his account with George Gilmer, apothecary of Williamsburg, for such things as oil of cinnamon, Holloways' Citrate, "Aqua Linnaean," rhubarb, sago, "Sal. Volat.," spirits of lavender, and gum fragac. The final item in the account was for April 22, 1750, for "a Vomit." The induced vomit, usually by a tartar emetic, was an accepted cure for overindulgence and a host of supposed ailments. That inveterate valetudinarian and amateur physician, William Byrd, was in the habit of "giving" vomits to his sick slaves.[114]
In November and December 1749 Mercer sustained his first long illness, during which he was attended by "Doctor Amson." "Taken sick" at home on November 13, he evidently did not begin to recover until December 11. Whatever improvement he may have made must have received a setback on the last day of the year, when he recorded in his journal: "Took about 60 grains of Opium & 60 grains of Euphorbium by mistake instead of a dose of rhubarb."
[112] Ten years earlier a vogue for rattlesnake root had been established, apparently by those interested in promoting it. On June 16, 1738, Benjamin Waller wrote to the editor of the _Virginia Gazette_ extolling the virtues of rattlesnake root in a testimonial. He claimed it cured him quickly of the gout, and, he wrote, "I am also fully convinced this Medicine has saved the Lives of many of my Negroes, and others in that Disease, which rages here, and is by many called a _Pleurisy_; And that it is a sure Cure in a Quartan Ague." Two weeks later the _Gazette_ carried "Proposals for Printing by Subscription a _Treatise_ on the DISEASES of _Virginia_ and the Neighbouring Colonies ... To which is annexed, An Appendix, showing the strongest Reasons, _a priori_, that the Seneca Rattle-Snake Root must be of more use than any Medicine in the _Materia Medica_."