Tutty

## Tutty Tutty

**Tutty** (zinc oxide, ZnO; Lat. *tutia* or *tutty*) is a white or grayish powder that forms as a sublimate in furnaces where zinc-bearing ores are smelted. Known since antiquity and described by Dioscorides and other ancient medical writers, tutty was used primarily in medicine as an external application for eye diseases, skin conditions, and wounds. The substance was collected from the flues and chimneys of brass-making furnaces (brass being an alloy of copper and zinc), where zinc oxide condensed as the zinc vapor oxidized. Different grades of tutty were recognized based on color and purity, with the whitest varieties considered most valuable for medical use.

In alchemy, tutty was less prominent than other metallic substances, but it appeared in various recipes and preparations. Some alchemists recognized a relationship between tutty and the production of brass, though the nature of zinc as a distinct metal was not fully understood until the early modern period. The substance's volatility (zinc oxide sublimes at high temperatures) and its formation as a furnace product associated it with the "spirits" or volatile principles in alchemical theory. In medicine, tutty was used in eye salves and collyria (eye washes), in ointments for burns and ulcers, and as a desiccant powder for wounds.

Modern chemistry recognizes tutty as zinc oxide, which indeed has mild antiseptic and astringent properties, explaining its traditional medical uses. The substance forms when zinc vapor (produced by heating zinc-bearing ores or metallic zinc) reacts with oxygen in the air. The historical production of tutty as a byproduct of brass-making reflects empirical knowledge of metallurgical processes, even though zinc itself was not isolated as a pure metal in Europe until the eighteenth century. The substance's medical applications have persisted: zinc oxide is still used in ointments, sunscreens, and other topical preparations. Tutty thus represents how metallurgical byproducts could become valuable medical commodities, and how practical knowledge of furnace operations informed both craft traditions and alchemical understanding.

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