The Prescription Records

John Snow's prescriptions were composed in a style that developed during the eighteenth century when advances in natural science and medicine encouraged a rationalization of the materia medica. In the second decade of the century a new edition of the Edinburgh Pharmacopoeia was cleansed of many of those "simples" or crude drugs which had been introduced by the credulity and superstition of former times.' This was followed by a thorough revision of the London Pharmacopoeia leading to the "reformed" edition of 1746. Here the list of crude drugs was drastically reduced and the majority of the items which had hitherto appeared under the headings 'Animalia', 'Metalica', and 'Mineralia' were no longer recommended.2 The critical and experimental revision of the London formulary also resulted in a farreaching simplification of the pharmacopoeial preparations. The Committee of the College of Physicians responsible for the new edition acknowledged the necessity of rejecting "irregular mixtures which the ignorance of the first ages introduced". Two exceptions to this rule were Mithridatium and theriac, described as alexipharmics or medicines framed to counter all poisons. These complex preparations had been severely criticized by William Heberden (17101801) in his essay Antitheriaka published in 1745.3 The Committee, however, retained them, pleading the "prevalence of custom" although the preface to the Pharmaccpoeia leaves little doubt that they were held in little regard.4 In 1756 these two ancient panaceas were dismissed from the Edinburgh Pharmalcopoeia giving official recognition to the follies of polypharmacy.5 The reform of the materia medica was accompanied by a revision in the manner in which medicines were prescribed. The most influential advocate for change was David Gaub (1705-80) of Leiden, who had studied under Boerhaave. In his book on the compounding of medicines, published in 1739, Gaub introduced a system of prescribing in a series of rules, the first being "Medicus, vir prudens, praescribat nihil, nisi cujus sufficientum queat redere rationen, cum requiritur": the physician should prescribe nothing unless he can render a sufficient reason for its use.6 The advantages of simplicity in prescribing were acknowledged by the Committee revising the London Pharmacopoeia. Strong medicines in combination with numerous other ingredients were seen to have their doses diminished and so rendered ineffective. As