Sir Hans Sloane presided over the compilation of the P.L. of 1721, the fourth of the series. The preface to this edition claimed that all remedies owing their use to superstition and false philosophy had been thrown out, but perhaps the far-reaching effects of the false philosophy were not fully appreciated. Many of the absurd old formulas were retained, but an approach to greater simplicity is apparent. The transition from the old to the new pharmacy can be traced very easily in this volume. The names of the plants, we are told in the preface, are “not only distinguished by the names known in shops, but also by such as are sometimes used by the more eminent writers in botany.” Tinctures are growing in favour, their number being increased to 18. The number of waters and syrups is largely diminished, and puppies, hedgehogs, wagtails, bread-crust plaster, lapis lazuli pills, and Galen’s unguentum refrigerans are dismissed. The last-named has, however, refused to die to this day. Among new chemical preparations Hepar Sulphuris (pot. sulphuret.), Flores Salis Ammoniaci Martiales (ammonio-chloride of iron), Tinctura Martis cum Spiritu Salis (tinct. ferri perchlor.), Sal Martis (ferri sulphas), Aqua Sapphirina (solution of ammonio-sulphate of copper), Lunar Caustic, Tartar Emetic, Ens Veneris, Aurum Mosaicum, Ethiops Mineral, Spirit of Sal Volatile, Mynsicht’s tincture of steel, Elixir of Vitriol, and Lime Water may be mentioned. The P.L. 1746 (the fifth) was very different from its predecessors. Among those who took an active part in its preparation were the President of the College, Dr. Plumptre, and Drs. Crowe, Mead, Heberden, and Freind. In the preface to this work the old “inartistic and irregular mixtures” and “the antidotes superstitiously and doatingly derived from oracles, dreams, and astrological fancies” are severely condemned, and the College declares its intention of freeing the book as much as possible from whatever remains of former pedantry. Notwithstanding these good intentions the old pharmacy is still abundantly represented. Crabs’ eyes, coral, bezoar stones, harts’ horns, woodlice, pearls, vipers, and skinks’ bellies continue to figure among the simples, and formulas for Mithridatium with 45 ingredients, and for theriaca with 61 are likewise retained. On the other hand, human fat, unicorn’s horn, mummy, spiders’ webs, moss from the human skull, bone from the stag’s heart, and lac virginale disappear. There are now 34 tinctures, while the medicated waters have been reduced to about 30 and the syrups to about 20. Tinctures of cummin, valerian, and cardamoms, syrup scilliticus, and pilula saponacea (soporific) are new; and lixivium saponarium (liquor potassæ), sal diureticus (potassæ acetas), causticum commune fortius (potassa cum calce), sal catharticus Glauberi, pilulæ mercuriales, and spiritus nitri dulcis make their first appearance.