The names of the ingredients are always written in Latin, for the following reasons:

1. Latin is a universal language, so is readable anywhere.

2. It is a dead language, so is not subject to change.

3. It is the language of science, so is explicit, and is not ambiguous. In the names of plant-drugs, for example, Aristolochia serpentaria always stands for the same plant wherever it is grown, while its English synonym, snakeroot, is applied to different plants in different localities.

4. It may be advisable to keep from the patient the nature of the drug. Patients have many preconceptions and prejudices regarding drugs. One patient assures the doctor that he is always made ill by calomel or phenacetin, yet obtains great benefit from a prescription for hydrargyri chloridum mite or acetphenetidin. Another has found cascara absolutely useless for his constipation, but secures a comfortable laxative movement from rhamnus purshiana.

Though prescriptions are written in Latin, prescription writing may be accomplished with very little knowledge of the language; for the construction follows rules that are not always those of classic Latin; and the customary methods of abbreviation enable one, without fear of criticism, to omit a Latin ending if the correct one is not known. Approved prescription writing, however, requires some knowledge of Latin and a familiarity with certain rules.

The following information about Latin words is not given with any intent to teach the language, but solely with the desire to facilitate prescription writing for those who do not know Latin.