As the existing British Pharmacopoeia, which is the second edition of that work, did not come into the possession of the author, though ordered from England at its first appearance, until he was approaching the close of the revision, and much the larger portion of the work had been printed, it necessarily follows that the references throughout the work to the British Pharmacopoeia are to the former edition, published in 1864. To have changed these references to the new edition, in the latter part of the work, would have given it a want of consistency which could scarcely be compensated by any benefit likely to accrue. But to put the reader in possession of the means of avoiding any serious misapprehension, it has been thought advisable to introduce, in the form of an Appendix, lists of the alterations which have been made in the new Pharmacopoeia, so that he may have the opportunity of comparing the two, and noticing in what they differ. The first list will include the new names which have been substituted for the old ones abandoned; the second, all the medicines and preparations which have been newly introduced; and the last two smaller tables, the preparations of the Pharmacopoeia of 1864 which have been altered or omitted.