The Pharmacopoeia is a book which defines and standardizes certain drugs and their preparations. Its aim is to establish definiteness for a selected number of those in extensive use by physicians. A number of the more enlightened nations have pharmacopeias, so there are the British Pharmacopoeia, the German, the Swiss, the Japanese, etc. For us, "The Pharmacopoeia" is the United States Pharmacopoeia (written "U. S. P."). Its drugs and preparations are spoken of as official. By the Pure Food and Drugs Act the National Formulary preparations have also official recognition. The official preparations are, therefore, the ones that are standardized; hence they are the preparations that can be obtained of uniform strength throughout the United States; and they are, for the most part, the forms in which remedies can be readily supplied by the pharmacist. Hence, the official preparations are the forms to be preferred by the physician in prescribing.

To illustrate the character of the Pharmacopoeia, take the drug strophanthus and its tincture. "Strophanthus" is defined as "the dried ripe seeds of Strophanthus Kombe and of S. hispidus, deprived of their long awns."The seeds of other species of strophanthus can be procured, but the pharmacist must not employ any but those of the species mentioned, and he must first remove the long awn, a spear-like projection at the apex of the seed which contains none of the medicinal ingredient. Furthermore it must respond to the requirements of a biologic assay on frogs, as given in the Pharmacopoeia.

For the tincture of strophanthus the Pharmacopoeia directs that 10 grams of strophanthus shall be taken to make 100 c.c. of the tincture, i. e., it shall be of 10 per cent. strength, it must be made with a certain specified menstruum, and it must have a certain physiologic activity. Therefore, when the tincture of strophanthus is prescribed, since it is an official preparation, the pharmacist is not entitled to dispense a tincture of any other strength or method of manufacture. On the other hand, if a physician prescribes an unofficial preparation, the pharmacist may dispense one of any arbitrary strength and made by any method convenient, and the physician is left in uncertainty about what his patient is getting.

The United States Pharmacopoeia gives information, also, about specific gravity, melting-point, solubilities, tests of identity, tests for impurities or adulterants, the average dose, etc. It is, therefore, an official formulary and book of standards, and is a working guide and dictator for the supplier of drugs, the manufacturer of preparations, and the pharmacist. It is not in any sense a book to be memorized by the medical student; but the choice of its preparations in prescribing favors accurate therapeutics.

The Pharmacopoeia is controlled and published by the National Pharmacopceial Convention, a gathering of delegates from the various medical and pharmaceutic colleges and state and national societies, and certain other selected societies, and from the Army, Navy, and Marine-Hospital Service. This Revision Convention meets every ten years (1890, 1900, 1910, etc.) at Washington, D. C, to determine the principles to govern the next revision. It also appoints a Committee of Revision to carry out the details of the revision, and administrative officers to issue the new edition when it is ready. Three or four years are then spent by the Committee of Revision in research and in the compilation of the revised book, which becomes official on a fixed date after it is issued. It is known as the Pharmacopoeia of 1890 or 1900, etc., the year of the Pharmacopaeial Convention. The present Pharmacopoeia is the Pharmacopoeia or revision of 1910; it became official on September 1, 1915. If a physician wishes to prescribe the formula of a previous pharmacopoeia, he must specify on his prescription, "U. S. P. 1880," "U. S. P. 1890," etc.

Because it recognizes so many seemingly needless drugs and preparations, the Pharmacopoeia has been much criticized. But it is to be borne in mind that the Pharmacopoeia does not consider merely the usefulness of an article, but attempts to standardize those drugs and preparations which are in extensive use by the recognized authorities in medicine in any part of the country. It must also standardize all substances used in making official preparations, whether or not of medicinal value.

The National Formulary is a book issued by the American Pharmaceutical Association, with the idea of standardizing some non-pharmacopeial preparations that are in common use. In a prescription the letters "N. F." following the name of a preparation (e. g., lotio plumbi et opii, N. F.) call for the dispensing of a preparation made according to the formula of this book.

A dispensatory is a commentary on drugs, a general reference work on the botany, pharmacognosy, chemistry, pharmacy, and therapeutics of drugs. It is an extensive work and is not official. The United States, the National, and King's Dispensatories are the best known in this country, and Hager's Praxis in Germany. They give a vast amount of information, and are encyclopedic in character, scarcely a known drug escaping some recognition.

Useful Drugs is a small book issued by the Council on Pharmacy and Chemistry of the American Medical Association. It presents a brief but practical discussion, from the modern viewpoint, of the properties, pharmacologic action, therapeutic uses and dosage of a list of drugs of approved worth. It should be in the hands of every practitioner.