At that date the science of chemistry was very imperfectly known, and the real constituents of ordinary remedies so little understood that different virtues were attributed to different products containing the same constituents.
They were probably very imperfectly prepared.
Woody or lignified cell-walls appear to contain substances called conifer-in and vanillin, in addition to various other compounds which are imperfectly known.
The specific effects of different impurities on the physical properties of zinc have only been imperfectly studied.
