In the second century of the present era Galen gave the definition that a remedial drug, or “Pharmakon,” was something which, when taken into the living body, produces an alteration in its component tissues or organs, whereas foods or nutrient elements simply cause an increase of the parts. He attached great importance to such characteristics as purity, freshness, care in handling, etc. It was his custom to prepare with his own hands the different combinations of simple remedial agents which he administered to his patients, and he kept these combinations, as well as the simple drugs of the more costly kinds, carefully stored in locked wooden boxes in a room which was devoted to this special purpose and which was termed the “Apotheke.” Originally, therefore, the “apothecary” was simply the person who had charge of this room in which the drugs and spices were carefully “placed to one side” (ἀπό, τίθημι) for safe keeping. At a later period, when the caretaker became also the compounder of drugs, another word of a more comprehensive significance--that of “pharmacist”--gradually supplanted the term apothecary. There is another word, “antidote,” which has very materially changed its significance during the lapse of centuries. Galen, for example, employed this word as a synonym of pharmakon--a simple remedial agent, and medical writers continued using the term in this sense during the following thirteen or fourteen centuries. The word commonly employed, by mediaeval physicians, to signify “pharmacopoeia,” was “antidotarium.” In modern times the word “antidote” signifies only an agent which neutralizes a poison.