It is but a few years ago that St. John Long had immense multitudes of patients in London, though his notions were of the most ridiculous character, and were attacked with the shafts of reason and ridicule on every side. His theory was, that all diseases were produced by a semi-mercurial fluid, and that in order to cure the disease, the seat of this fluid must be found, and the fluid must in some way be got out. He had discovered a very summary way of doing this. He used a liniment, which he applied over the seat of the fluid, and extracted it at once. Though this liniment had such wonderful power, it would produce no effect when applied over a part which was not diseased—so that in any case, in which the seat of the disease was not obvious, instead of going through with a strict and long investigation after the vulgar way of regular doctors, St. John Long only had to apply his liniment here and there, till he found that the disease was extracted. One would hardly suppose that such nonsense could be believed in any civilized community; but the theory of this painter, who had thrown aside his brush and dubbed himself doctor, ridiculous as it was, found such favor with the public, that the prominent journals came out with weighty articles against it. Reasoning was not only in vain, but worse than in vain. The wonder grew—it was not put down. Quackery never yet was _killed_—it always _dies a natural death_, and so did the quackery of St. John Long. After running the gauntlet amidst the heavy blows of wise and powerful enemies, and coming forth unharmed at every heat, it at length laid itself down, and died the most quiet death imaginable. It fell asleep; and this is the end of all quackery. Who has not heard of Perkins’ Tractors? The inventor, Doctor Elisha Perkins, was born in the town where the author resides. He was the son of a physician, who was for forty years in extensive practice, and was himself, for some time a respectable physician in the town of Plainfield in this State. He was undoubtedly an honest man. He duped others, it is true, but he duped himself, too. He was a deluded enthusiast, and died a victim to his enthusiasm only three years after he published to the world his grand ‘discovery.’ He had conceived the idea that a free use of salt as an antiseptic would cure the yellow fever. He therefore went to New York in the year 1799, when this disease was raging, and, full of confidence in his mode of practice, offered his services most generously to the poor as well as the rich. At the end of four weeks he himself caught the fever, and being exhausted by his labors he survived but four days after his attack.