The abolishment of the apothecaries' system meant that doctors' prescriptions had to take place in terms of the current civil weight: grammes and kilograms. This was considered unfeasible by many, and the state received numerous protests and asked for expertises. Nevertheless, by 1868 §4 of the earlier reform was finally put into force. Metrication in countries using the troy and avoirdupois systems Britain was initially involved in the development of the metric system, and the US was among the 17 initial signatories of the Metre Convention in 1875. Yet in spite of enthusiastic support for the new system by intellectuals such as Charles Dickens, these two countries were particularly slow to implement it. To unify all weight systems used by apothecaries, the Irish pharmacopœia of 1850 introduced a new variant of the apothecaries' system which subdivided a new apothecaries' pound of 12 avoirdupois ounces instead of the troy pound. To allow effective use of the new system, new weight pieces were produced. Since an avoirdupois ounce corresponds to 28.35 g, the proposed system was very similar to that in use in Portugal and Spain, and in some locations in Italy. But it would have doubled the value of the avoirdupois drachm (an existing unit, but by then only used for weighing silk). Therefore, it conflicted with other non-standard variations that were based on that nearly obsolete unit. The Irish proposal was not widely adopted, but British legislation, in the form of the Medicinals Act 1858, was more radical: it prescribed the use of the avoirdupois system for the United Kingdom (then including Ireland), with none of the traditional subdivisions. This innovation was first used in the United British pharmacopœia of 1864. In practice the old apothecaries' system based on the troy pound was still widely used, however, until it was abolished by the Weights and Measures Act of 1976, since when it may only be used to measure precious metals and stones. (The troy pound had already been declared illegal for most other uses by the Weights and Measures Act of 1878.) In the US, the metric system replaced the apothecaries' system in the United States Pharmacopeia of 1971. See also List of abbreviations used in medical prescriptions List of Latin abbreviations Notes and references Further reading External links Apothecaries' symbols Online Apothecaries' Converter Pharmacopoeia pro Republica Augustana, 1613 Pharmacopoeia Collegii Regalis Londini, 1677 Pharmacopoea Collegii Londinensis Medicor, 1746 Obsolete