Step 1: Understanding the Concept:
A prescription is a written order from a registered medical practitioner to a pharmacist.
It consists of several standard parts, each serving a distinct function in the dispensing process.
Step 2: Key Approach:
To answer this question, we need to know the specific terms used for each section of a traditional prescription.
Step 3: Detailed Explanation:
The Superscription includes the date, patient details, and the symbol Rx, which stands for the Latin word 'Recipe' meaning 'take thou'.
The Inscription is the main body of the prescription, containing the names and quantities of the prescribed medication or ingredients.
The Subscription provides specific dispensing instructions from the prescriber to the pharmacist, such as the dosage form and the number of doses to be dispensed.
The Signa (often abbreviated as Sig.) contains the directions for the patient, which the pharmacist translates onto the prescription label.
Therefore, the subscription is the part specifically directed at the pharmacist.
Step 4: Final Answer:
The part of a prescription containing instructions to the pharmacist is the Subscription.