In this chapter only the drugs of the British Pharmacopoeia are considered. For the convenience of the student and for the purpose of reference, the drugs have been arranged in alphabetical order, save that the preparations of any drug immediately follow it. As preparations of any drug are considered such galenicals as bear the name of the drug as an important part of their title, (under this rule Pilula Saponis Composita is classed as a preparation of Sapo.) or such galenicals as contain the drug as their important constituent, (under this rule Pipula Saponis Composita is classed also with Opium). That a galenical is considered as a preparation of a drug is indicated by its name being set further from the margin (indented) than is the name of the drug under which it is classed as a preparation. This rule is adhered to for galenicals but certain of the active principles, such for example as Atropine, though classed with the preparations of Belladonna, are treated in all other respects as separate drugs. There are also several galenicals especially among the Liquors, e.g. Liquor Trinitrini, whose active principle is not official, and these will be found classed according to their official name. The titles of galenicals are as a rule placed immediately after the preparation from which they are prepared and their title is again set further from the margin of the page. The salts of any base appear under the general heading of the base as though they were preparations of it.

Further for the advantage of the student the drugs have been divided into four classes, *indicating their relative importance. The names of drugs of the first class, those of pre-eminent importance, are printed thus Opium: these drugs the student must master thoroughly. The drugs of the second class have their names printed thus, Acetanili-dum: these drugs should also be thoroughly studied. In the third group are included many useful and frequently used drugs, and with them the student should be familiar: their names are printed thus, Acacia Gummi. The drugs of the fourth class are of minor importance in use or in activity: their names are printed thus, Ammoniacum. Even important drugs have, however, preparations that vary amongst themselves in importance from the practical standpoint, and an attempt has been made to indicate this by placing before their titles a superior numeral, thus, 1Tinctura Opii. The superior numeral one will indicate that the preparation is of importance, the numeral three will indicate that the preparation is relatively of no importance: the numeral two indicates roughly a preparation of an importance mid-way between the other two. It will be noted that drugs of the fourth class have as a rule preparations without a numeral prefix In some cases none of the preparations of a drug seemed worthy of the numeral one or even of the numeral two, this indicates that the drug is much more important than any of its preparations.

*The author thoroughly realizes that any such classification of drugs and of preparations as has been adopted is open to criticism both in principle and in the details of the classification itself. Any such classification must be largely a personal one. It has, however, been resorted to it with the view of aiding the student.

The official Latin name of the drug is always given; its English equivalent only when difficulty might arise in translating the Latin or where other considerations seemed to render the giving of it an advantage. Important synonyms are in many case also given: they are always enclosed in brackets. The dose is given in both the Imperial and the Metric systems. The Imperial as being the official dose is given the preference. The doses in the Metric system are as a rule those of the British Pharmaceutical Codex, though the term "mil" and its diminutives in spite of its very obvious advantages have not been adopted. Doses enclosed in brackets are not official.

No attempt is made to give the full Pharmacopceial definition of any drug or description of its physical or chemical characters, enough only is given to draw the attention of the student to some of its outstanding characters a knowledge of which may be of advantage to him. The formulŠ for the preparation of galenicals are as a rule taken from the British Pharmaceutical Codex. In this the Pharmacopaeial formulae have been recalculated so that the total of the quantities of the ingredients at the end of the process of preparation will aggregate 100. The advantages of this centesimal system are obvious, the principle one, being the ease with which the percentage strength of any ingredient may be seen. It is an added advantage in a laboratory where the dispensing is carried out in the Metric system. No attempt has been made to give a detailed description of the steps to be pursued in the preparation of any galenical, but only enough is indicated to aid the student to use them intelligently in dispensing and prescribing. For a knowledge of the steps in preparation of galenicals the student is referred to the Pharmacopoeia or the Codex. Where the formula of any preparation is given the first quantity preceeded by a dash indicates the quantity of the drug or preparation under which the preparation in question is classed.

The more important solubilities of the drugs are also given and are stated for room-temperature, 15.5 C, unless the word "hot" is used as meaning boiling (by cold is meant 15.5 C as opposed to boiling). Solubilities are always expressed in parts by weight. By water, distilled water is always meant and by alcohol, 90% alcohol (Rectified Spirit).

The important incompatibilities are given with often an indication of the chemical change occuring. In some cases methods of overcoming or lessening the incompatibility are also given.