Determining a Drug's Properties: Medieval Experimental Protocols.

Among Galenic texts attracting attention circa 1300 was De complexionibus, which described a crude protocol for determining the qualitative character and intensity of any given medicine. This caught the attention of physicians at Montpellier, where three generations of writers made it into a carefully structured test procedure for identifying by a via experimenti the nature of a drug's effect on healthful function: they introduced a null point as the referent for their measurements, identified a range of contingent factors that had to be controlled for, and devised ways to standardize the sample being tested. Their protocol was certainly designed to be used, but in practice they seemed to have preferred an alternative via rationis that inferred the effect of a medicine from sensory attributes like taste and color, acknowledging that taste tests were coarser and less certain than a structured experimental procedure, but were easier and quicker to perform than the elaborate alternative.