Thus there exists a fashion in medicine, as in the other affairs of life, regulated by the caprice and supported by the authority of a few leading practitioners, which has been frequently the occasion of dismissing from practice valuable medicines, and of substituting others less certain in their effects and more questionable in their nature. As years and fashions revolve, so have these neglected remedies, each in its turn, risen again into favour and notice, whilst old receipts, like old almanacks, are abandoned until the period may arrive, that will once more adapt them to the spirit and fashion of the times. Thus it happens that most of our “_New Discoveries_” in the Materia Medica have turned out to be no more than the revival and adaptation of ancient practices. In the last century, the root of the _Aspidium Filix_, the Male Fern, was retailed as a secret nostrum by Madame Nouffleur, a French empiric, for the cure of tape worm; the secret was purchased for a considerable sum of money by Louis XV. and the physicians then discovered that the same remedy had been administered in that complaint by Galen.[65] The history of popular medicines for the cure of Gout, will also furnish us with ample matter for the illustration of this subject. The celebrated Duke of Portland’s Powder was no other than the _Diacentaureon_ of Cælius Aurelianus, or the _Antidotos ex duobus Centaureæ generibus_ of Ætius,[66] the receipt for which a friend of his Grace brought from Switzerland; into which country it had been probably introduced by the early medical writers, who had transcribed its virtues from the Greek volumes soon after their arrival into the western parts of Europe. The active ingredient of a no less celebrated remedy for the same disease, _the Eau Medicinale_,[67] has been discovered to be the _Colchicum Autumnale_ or Meadow Saffron; upon investigating the properties of this medicine, it was observed that similar effects in the cure of the gout were ascribed to a certain plant, called _Hermodactyllus_[68] by Oribasius and Ætius, but more particularly by Alexander of Tralles,[69] a physician of Asia Minor in the fourth century; an inquiry was accordingly instituted after this unknown plant, and upon procuring a specimen of it from Constantinople, it was actually found to be a species of _Colchicum_. The use of Prussic acid in the cure of Phthisis, which has been lately proposed by Dr. Majendie, and introduced into the _Codex Medicamentarius_ of Paris, is little else than the revival of the Dutch practice in this complaint; for Linnæus informs us, in the fourth volume of his “_Amænitates Academicæ_,” that distilled Laurel water was frequently used in Holland for the cure of pulmonary consumption.