Ad libitum (ad lib), at pleasure. Ad saturdndum (ad sat.), to saturation. Ana (da), of each. Bene, well, Bis, twice.

Bis in die (b. i. d), twice a day.

Cibus, food.

Cochleare medium (cochl, med.), a dessertspoon(ful).

Cochleare magnum (cochl. mag), a tablespoon(ful).

Cochleare parvum (cochl. parv), a teaspoon(ful).

Collutorium (collut), a mouth-wash.

Dein, afterward.

Dimidius, half.

Dosus (dos.), a dose.

Et, and.

Extende supra, spread upon.

Gradatim, gradually.

Gutta (gtt), a drop.

Guttatim, drop by drop.

Horn, an hour.

In die, daily.

Lagena, a bottle.

Libra, a pound.

Linteum, lint.

Mane, in the morning.

Mane primo, early in the morning.

Mica panis, a breadcrumb.

Non, not.

Nocte, at night.

Numerus, a number.

Numero (No.), in number.

Octavius (O.), a pint.

Omne die (o. d.), every day.

Omne mane (o. m.), every morning.

Omne nocte (o. n.), every night.

Partes aequales (part, aeq.), in equal parts.

Pro re nata (p. r. n.), as required.

Quantum sufficiat (q. s.) as much as is necessary.

Quaqua hora (q. h), every hour.

Quaqua quattuor hora (q. q. h.), every four hours.

Saturatus, saturated.

Scatula (scat), a box.

Semel, once.

Semissis (ss), a half.

Semidrachma, (3ss), half a dram.

Simul, together.

Sine, without.

Si opus sit (s. o. s), if necessary.

Statim (stat), immediately.

Tales (tal), such.

Tales doses (dos. tal), such doses.

Tere simul, rub together.

Ter in die (t. i. d), three times a day.

These complete the list of Latin parts of speech, conjugations, declensions, etc., with which the prescription writer is likely to be concerned.

We are now prepared to analyze a simple prescription and understand its elements.

Suppose we wish the druggist to supply three drams of olive oil. We prescribe as follows:

It must be borne in mind that the direct object of the imperative recipe in this example, as well as in all similar cases, is not the word oleum, but the word drachmas representing the amount of it prescribed, as indicated by the Roman numerals and the symbol of Apothecaries' Weight, which, written in full, would be tres drachmas (acc). In this class of prescriptions, therefore, including nearly all in use, we need consider only the genitive, the accusative, or grammatical object of the verb being expressed in the quantity symbolically indicated.

It will be noted, moreover, that the construction, or order, of the Latin words is the reverse of English usage. Yet it is evident that a grocer's clerk, for instance, might well, and frequently does, employ the same mode of expression: (of) Granulated Sugar, lbs. 10 a construction precisely analogous to that of the above prescription, which simple form may be taken as a type for all, subject to such modifications as the nature of the drug and the treatment may require.

There are niceties of Latin construction which, to one acquainted with that idiom, will readily occur in scanning the order of words in certain medicinal compounds. Having the sanction of professional usage, the departure from the classic arrangement is of slight importance, and it is certainly in accordance with the clearer, more direct, English form. Instance the construction in what are known as "Galenical Preparations" (an objectionable adjective, by the way, being at variance with the rules of etymology, since the c of the derivative is wanting in the parent word Ga/en). In writing these, the nominative - uentum, Mistura Tinctura, etc. - is placed first, as, Unguentum Zinci Oxidi, etc. Oleum Morrhuae is also an example, and others are not uncommon, apart from the Galenical order.

The practical difficulties in writing prescriptions correctly are largely eliminated by the almost exclusive use of the genitive. Yet it is necessary to understand clearly the use of the accusative in all cases where the medicine is made into objects, as powders, capsules, etc. The names of such are the immediate object of the imperative recipe, and cannot be placed in the genitive.

Example:

R. Pilulas (not Pilularum) Ferri Iodidi (No. xii).

Where the mass is mentioned or implied in the prescription the general rule of the genitive is followed, as: R. Unguenti Belladonnas (a portion); and where the terms fiat, fiant are expressed, the nominative is naturally used, as, for example, R. Massae hydrargyri, gr. xxx;

Flant pilulae No. x. Sig. Take one at bedtime.

Here pilulae is the subject of the Latin irregular verb signifying "to be made," no case save the nominative being admissible. We may, however, write " fiat (or fiant) in pilulas No. x," the subject of the verb being the word for ingredient or ingredients (understood).

It has been presumed in the foregoing pages that all prescriptions are to be written in full - a practice which, could it meet with universal acceptance, would not infrequently be of vital importance alike to patient and practitioner. Custom, however, - and in certain cases advantageously - has authorized the extensive use of abbreviations, although the dangers of carelessness or ignorance in their employment will be apparent if we consider that, for example, Amnion, may mean either Ammonia or Ammoniacum; Chlor., Chlorum, Chloral, Chloroformum, Chloras, or Chloridum; Hyd. Chlor., Hydrate of Chloral or Hydrargyri Chloridum Corrosivum or Mite; Sulph., Sulphur, Sulphas, Sulphidum, or Sulphis; Zinc. Phos., Zinci Phosphas or Zinci Phosphidum.

These are but few of the many instances of ambiguity occasioned by inadvertence or want of familiarity with the full Latin form, or at least its recognized and unmistakable abbreviation.

In conclusion, let the writer of prescriptions be warned against too great haste and a chirography which none but its author can decipher - a deficiency for which he alone is responsible, though the onus may fall upon the luckless druggist or his bewildered clerk.