The great enthusiasm shown by Rivière for the above-mentioned remedy does not, however, derive from a long experience, made by himself or by others, of its advantages, but is based principally on a fact referred to by Montanus, and which,[345] we will here recount, because, from it, one clearly perceives how credulously our forebears accepted general affirmations and formulated therapeutic precepts. Montanus recounts in one of his writings, how, being in Rome in his early youth, he became acquainted with a woman of about twenty years of age, known by the name of Maria Greca (by the way the author speaks of her, one is led to suspect she was a courtesan); and how, having seen her again, thirty years later, and found her in pretty much the same conditions as formerly, he expressed his surprise at this; whereupon Maria Greca told him that she herself believed that she owed the conservation of her beauty to the habit, already of many years’ standing, of using one or two drops of oil of vitriol every morning, as a friction for the teeth and gums. In her youth she had had very bad teeth, but by reason of this cure they had become, and were at the time being, beautiful and perfectly firm; the gums also were in excellent condition; it seemed, therefore, to her that this conservation of health and freshness, in spite of her fifty years, depended precisely on the daily use, in the manner described, of oil of vitriol![346] Rivière, besides, recommends tobacco ashes for cleaning the teeth, a counsel not yet given by any previous author. He also gives the formulæ for two dentifrice powders, the basis of which is alum; he calls attention to the great importance of taking assiduous care to keep the teeth clean, and advises that after each meal the residues of food be removed from the interstices of the teeth and the mouth well rinsed with wine.[347] NICOLAUS TULP, in Latin, Tulpius (1593 to 1674), a distinguished physician and anatomist of Amsterdam, contradicts the then prevailing opinion among doctors, that is, that the cure of dental affections and the operations relating thereto were matters to be held in little account. He observes that diseases of the teeth may give rise to the most serious consequences, which can even be the cause of death, and are, therefore, worthy of being taken into equally serious consideration as all the other diseases of the several parts of the human body.