This “Lover of the Lamb of God” was a half-crazy old woman, named Mary Pratt, who conceived for Mr. and Mrs. de Loutherbourg a veneration which almost prompted her to worship them. She chose for the motto of her pamphlet a verse in the thirteenth chapter of the Acts of the Apostles: “Behold, ye despisers, and wonder and perish! for I will work a work in your days which ye shall not believe, though a man declare it unto you.” Attempting to give a religious character to the cures of the painter, she thought a woman was the proper person to make them known, since the apostle had declared that a man should not be able to conquer the incredulity of the people. She stated, that from Christmas 1788 to July 1789, De Loutherbourg and his wife had cured two thousand people, “having been made proper recipients to receive divine manuductions; which heavenly and divine influx, coming from the radix God, his Divine Majesty had most graciously bestowed upon them to diffuse healing to all, be they deaf, dumb, blind, lame, or halt.”
In her dedication to the Archbishop of Canterbury she implored him to compose a new form of prayer, to be used in all churches and chapels, that nothing might impede this inestimable gift from having its due course. She further entreated all the magistrates and men of authority in the land to wait on Mr. and Mrs. de Loutherbourg, to consult with them on the immediate erection of a large hospital, with a pool of Bethesda attached to it. All the magnetisers were scandalised at the preposterous jabber of this old woman, and De Loutherbourg appears to have left London to avoid her,—continuing, however, in conjunction with his wife, the fantastic tricks which had turned the brain of this poor fanatic, and deluded many others who pretended to more sense than she had.