Organon §91
Treatment of patients on medication.
The befallments and condition of a patient during some previous course of medication do not give the pure image of the disease. On the other hand, symptoms and ailments suffered before the use of the medicine or several days after discontinuing its use give the genuine, fundamental concept of the original gestalt of the disease, and the physician must record these in particular.
When the patient has a protracted disease and has been taking medicine up until the time of the visit, the physician could also leave him several days entirely without medicine or give him something non-medicinal [i.e. , a placebo], postponing for several days the more exact scrutiny of the disease signs in order to apprehend the enduring, unmixed symptoms of the old malady in their purity, and then be able to sketch an unmistakable image of the disease.