Despite the attacks of Kunkel, Boerhaave, the elder Geoffroy, Klaproth, and other chemists of influence and repute, alchemy died hard. It found believers in England until near the close of the eighteenth century, and was professed even by a Fellow of the Royal Society—Dr. James Price, of Guildford, who, in chagrin at the exposure of his pretensions, put an end to his existence in 1783. Hermetic societies existed in Westphalia, at Königsberg, and at Carlsruhe down to the first decade of the nineteenth century. M. Chevreul, who lived well into that century, relates that he knew of several persons who were convinced of the truth of alchemy, among them “generals, doctors, magistrates, and ecclesiastics.” The strange medley of alchemy, theosophy, thaumaturgy, and cabalisticism professed by Christian Rosenkreuz is not without its adherents, even in this twentieth century. If the baser metals have not been made to furnish gold, truth at least has followed from the practice of error. This is the only transmutation which the art of Hermes has succeeded in effecting. To err is human. Although alchemy is not without its special interest as one of the most remarkable aberrations in the history of science, some of its practitioners, it must be admitted, deceived only themselves: if misguided, they were at least honest, and pursued their calling in a settled conviction of the soundness of their faith. Although they never reached their goal—the discovery of the Philosopher’s Stone and the Elixir of Life—their labours were not wholly vain, for many new and unexpected facts came to light as the result of their assiduity. “Credulity in arts and opinions,” wrote Lord Bacon in _De Augmentis Scientiarum_, is likewise of two kinds—viz., when men give too much belief to arts themselves, or to certain authors in any art. The sciences that sway the imagination more than the reason are principally three—viz., astrology, natural magic, and alchemy.... Alchemy may be compared to the man who told his sons that he had left them gold, buried somewhere in his vineyard; while they by digging found no gold, but by turning up the mould about the roots of the vines procured a plentiful vintage. So the search and endeavours to make gold have brought many useful inventions of light. CHAPTER V IATRO-CHEMISTRY The term “iatro-chemistry” denotes a particular phase in the history of medicine and of chemistry. The iatro-chemists were a school of physicians who sought to apply chemical principles to the elucidation of vital phenomena. According to them, human illnesses result from abnormal chemical processes within the body, and these could only be counteracted by appropriate chemical remedies. Although this idea did not originate with him, the chief exponent of this school is commonly said to be Paracelsus.