[ORIGINAL COMMUNICATION.]

REMARKS ON THE DIGEST OF CRITICISMS ON THE U. S. PHARMACOPOEIA.

BY PROF. CHAS. T. P. FENNEL, CINCINNATI, O.

I. GENERAL TOPICS.

Specification of Time.-The date on which the new Pharmacopoeia goes into effect should be definitely fixedJuly 1st, 1891. This date would give ample time for the revision and the publication, especially under the present conditions.

Nomenclature and Language.-The text should be in the English language, the titles should be in the Latin. The text is intended for the pharmacist, the title for the physician. The Latin language is chosen for the latter, since the terms are more concise and less cumbersome in phraseology; being a dead language, it is not so liable to changes. The English titles are more for convenience than for any practical purpose. In many instances these terms give but superficial information.

Tscheppe's remarks in the Pharm. Rundschau are well taken and should receive full consideration by the Committee on Revision. The question will be, Shall the terms be strictly scientific or rather conform with terms in common usage? The former will give a very cumbersome term in many instances, but true to the exact nature, structure, and composition of the substance. The terms of common usage are generally short and consequently deficient in definition. To follow either course exclusively would be unsatisfactory-a compromise must be effected, and this can only be accomplished by adopting both methods. Qualifying adjectives are in many instances necessary to prevent misunderstanding. Thus Aconitum (scientific method) refers to the whole plant, and consequently the officinal preparation would require the prefix Radix, governing the genitive case. But if Aconitum (present or common usage) is understood to mean nothing but the tuberous root, the prefix is entirely unnecessary. Standards.-All crude drugs and galenical preparations should be standardized. Crude drugs should be valued according to the amount of chief active constituent contained in them (determined by approved and specified methods). The secondary and other constituents must bear some definite relation to the principal one, and as a natural consequence insure therapeutic value to preparations of these. Unless crude drugs meet certain specific characteristics and are standardized as to strength, they deserve no place in the Pharmacopoeia. The description of crude drugs depends upon the method adopted in the nomenclature, necessitating a description of the plant and the part used.

Assays. It naturally follows that if crude drugs are standardized a method for determining strength must be incorporated in the Pharmacopoeia. These assays should be as simple as possible, requiring apparatus at the disposal of every pharmacist. The results will of course be only approximate, but at least form a good guide for the limit of strength.

Adulterations.-These should not enter into the Pharmacopoeia. The description of all drugs applies only to the pure article, and there is therefore no necessity for calling attention to probable admixtures. The limit of by-products should be mentioned.

Specification of Strength.-If the foregoing is followed, the strengths will be specified.

Specific Volumes.-The term "specific volume" was, it seems, coined by Prof. O. Oldberg to express the relative volumes of liquids in the same sense that specific gravity expresses relative weight. A knowledge of the laws of specific gravity furnishes a simple method for calculating the volume of a liquid when its weight and specific gravity are known, and, conversely, its weight when volume and specific gravity are known. Specific gravity may be expressed by the formula: Specific gravity= absolute weight ; therefore absolute weight specific volume gravity x volume, expressed in the corresponding weight. absolute weight Volume =

ing measure.

and decrease of volume, is discussed in Fennel's "Principles of General Pharmacy" (pp. 29-43).

The tables of specific volumes that have been computed are of service in many instances, but their main object has been defeated. The application of these tables for parts by weight does not simplify the formulæ of the Pharmacopoeia. The subject of specific gravity is but little understood and much less applied. The subject of specific volume will fare no better, and is, therefore, practically of no value. If the weighing of liquids is so objectionable, the revisers of the next Pharmacopoeia should be instructed to substitute parts by measure for liquids. But if the system "parts by weight" is to be retained, it seems far more rational to adopt the general rule based upon the laws of specific gravity and translate the language of weight to that of volume by calculation. That the volume of a liquid is most accurately obtained by weighing there can be no doubt. Judging from the literature on the subject, the primary consideration seems to be convenience, and the method not meeting that want is condemned.

Specific Gravity.-This question has received so much consideration by able men, notably Drs. A. B. Lyons and E. R. Squibb, that but little remains to be said. The Pharmacopoeia is intended for the benefit of the pharmaceutical profession as a whole and not for a few scientists, and therefore the requirements should meet the wants of the majority. There is no necessity of prescribing a uniform method for the taking of specific gravities of liquids; no matter what method is pursued, the results must be the same under like conditions. The results desired and obtained in the pharmaceutical practice can be but approximate, and, consequently, the apparatus need not be of exceptional accuracy. To obtain exceedingly fine results would require fine, delicate, and accurate apparatus, principally scale, weights, and thermometer, all beyond the means of the general pharmacist. Furthermore, it would be necessary to consider the forces, temperature, and atmospheric pressure, and the influences exerted by these during operation. Some basis for comparison must be adopted, but this basis must be definitely stated and remain such for the determination of specific gravity of all pharmacopoeial preparations. This standard of comparison by universal custom and consent is that of pure water, free from air, necessarily distilled, and recently boiled. The standard temperature adopted by scientists is 4° C. = 39.2° F. In every-day practice, this temperature is not convenient for weighing liquids, requiring their cooling with consequent loss of time and involving considerable labor. It is, therefore, desirable to adopt a temperature more readily commanded during the year, namely, 20° C. = 68° F. The specific gravity of liquids of the Pharmacopoeia should therefore be determined in comparison with water at the temperature of 20° C. taken as unity. It would be utterly impracticable to force upon the pharmacist the determination of specific gravities upon a strictly scientific basis. It would involve the specification of the size and nature of the specific-gravity flask, the coefficient of expansion, both of vessel and water, for every degree of temperature, and the consideration of atmospheric pressure and thermometric corrections. Thus 1 volume of water at 4° C. is increased to 1.000848 volumes at 15° C.; to 1.00179 volumes at 20° C. This 1 volume at 4° C. is considered unity, and specific gravity 1.0000. The increase of volume at 15° C. (0.000848) would, according to the general principle, Abs. W. vol. x spec. grav. expressed in the corresponding weight, weigh 0.000848, and the specific gravity of the same volume at15° C. be 0.999152. The correction necessary, owing to expansion of the glass, would be computed for 11° C. at 0.00254 for each 1o C., reducing the specific gravity to 0.9988726; the calculation being based under standard barometric pressure of 30 inches (760 Mm.) The errors arising from thermometric inaccuracies, especially in a long range of degrees, are considerable. To guard against them requires careful and skilful manipulation and special apartments for performing the operation. The pharmacist in general will find it next to impossible to determine specific gravities under these conditions. The adoption of 20° C. for temperature, and considering water as unity at that temperature, making no allowance for expansion, will make the determination of specific gravities feasible and prac

ounce.

The Troy ounce has no corresponding measure.
The subject of specific gravity, absolute weight, increase

Gallon, U. S.-The standard gallon is not a measure of great precision, since the weight of a cubic inch or other linearly-measured volume of water is not accurately known. The systems of weight and measure have come to us by inheritance from the English, and until the question is settled by legal enactments, the gallon and other measures of capacity will remain a variable quantity. The systems of weight and measure are derived from a measure of length; and this measure of length, which is the