The subscription as here considered consists of the prescriber's directions to the compounder. It is usually written in Latin and almost always abbreviated; so the terminations are of no practical importance.

The primary consideration, here as elsewhere, is for the prescriber to so express his wishes that there is no possibility for any misinterpretation, and if this cannot be done in Latin, it is certainly better to use good English.

Many of the abbreviations employed are so commonly used that there is no possibility of any misunderstanding as to what is intended, but many of those found in some textbooks and occasionally used are little known and unsafe.

Brevity is always a consideration, but should not be used at a sacrifice of completeness. The prescriber should say all that is necessary and then stop.

In a large percentage of prescriptions the single abbreviation M. (misce-mix) is all that is required. It is always wise to avoid telling the pharmacist to do something that is obviously necessary, as M. et ft. sol., when the ingredients are such that they could not be mixed without making a solution, or M. et ft. ung. when an ointment is the only possible result of following the directions, M. M. S. A. (mix according to art) is always unnecessary, as the compounder is naturally going to employ the art of compounding to the best of his ability and understanding.

When the medicine is to be put into doses it is necessary to indicate the form of administration. The directions to the compounder may then be written, as M. ft. cap. no. x, or M. ft. pil. no. x, or M. ft. cht. no. x, etc.

When a special form of preparation is desired and it would be possible to make some other, it is best to specify, as M. ft. emul.

When it is desired to emphasize any particular point in compounding it may be specified, as when a solution is wished and it will take some effort to get one or more of the ingredients to dissolve. A druggist might not be familiar with the solubilities and merely mix the ingredients without triturating, depending on solution being effected before the preparation reaches the patient. Under such circumstances it is best to specify solution and, if the solid will not then dissolve entirely, the preparation cannot be dispensed without the prescriber's further instruction. An example would be:

M. ft. sol.

When it is particularly desired that the ingredients in a powder or ointment should be well incorporated, it should be specified. An example would be in the following prescription for the eye:

M. et tere bene.

When it is desired to explain at length some particular matter as to the compounding, it is often better to mark in the lower left-hand corner {over), and on the back of the paper explain fully in plain English what is wished.