Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. While the immediate reason for a revision of this work was to bring the book into accord with the ninth decennial revision of the United States Pharmacopoeia, yet the principal changes have been made on extra-pharmacopoeial matter. Most of the subjects have been enlarged by a selection of matter that is likely to be of use at the prescription-counter.