CHEMICAL SOLUTIONS- Reagents Useful to the Chemist, Biologist, and Bacteriologist by FRANK WELCHER. PREFACE: Every practicing chemist and teacher of chemistry is constantly required to prepare special solutions and reagents of all kinds as a fundamental part of his work. These solutions, which include indicators, standard acids and bases, solutions of salts, special test reagents, stains, fixatives, culture media, etc., are among the basic materials which are essential to all laboratory work. The directions for preparing these solutions are not always con veniently available, and are usually found only in a reasonably complete chemical library. Since most laboratories do not have adequate library facilities, a book of formulas for the more commonly used solutions is an extremely useful addition to the laboratory shelf. The purpose of this book is simply to collect in one place for convenient reference the methods for preparing those solutions most frequently re quired by the chemist. In order to increase its usefulness, however, much additional information has been included for each of the solutions to supple ment the preparative methods. This includes ( a) the uses of each solution; ( b) the procedure for use of each in all cases where this is practicable; ( c) a list of those substances which interfere in making special tests; ( d) the sensitiveness of test reagents; and ( e) general remarks regarding the keep ing qualities, methods of storage, etc., of the various reagents. In addition to this practical information, one or more references has been included for each solution in all cases where a useful citation is available. The purpose of this list is intended to be purely utilitarian rather than historically com plete, and so in many cases no reference to the original publication is in cluded. Rather, an effort has been made to refer where possible only to standard and easily available books and periodicals, preferably in the English language. The subject matter has been selected from the literature covering all phases of chemical laboratory work, and is designed to serve chemists engaged in all branches of their profession. The solutions are listed in alphabetical order under the name by which they are best known. When a reagent is known by more than one name, the various names are included in their proper place in the alphabetical tabulation with proper cross-reference. An index of the reagents, which are classified according to their uses, is provided to assist the chemist in locating solutions whose functions are known, but which are not listed by the name known to him. This index is also of value in suggesting reagents for various tests with which the chemist is not familiar, or for which known reagents are not suitable.