A symbol and a storage jar
Carboys have become a recognisable symbol of pharmacists worldwide. A good example, complete with colourful contents, is displayed in the shop window of Castelow's chemist shop which is now recreated in the Streetlife Museum, Hull.
The term carboy comes from the Persian word qarabah or qarrabah, meaning "large flagon." It is thought that carboys originate from the Near East, where drug sellers used large glass vessels, filled with coloured liquids, especially rosewater and wine, in their stalls.
Adopted by pharmacists
The use of the carboy as a symbol for pharmacists dates back to 1600 when they were used to distinguish between pharmacists and apothecaries (who used a pestle and mortar as their sign). In the 1700s they became even more familiar as a pharmaceutical sign when shop windows were made in bigger panes and large window displays were possible. As a result, ornamental carboys became a familiar window decoration.
The most popular designs were the 'onion,' the 'pear' and the 'swan neck' shaped carboys. The vessels are impressive not only because of the shape and size but the brightly coloured liquid that was, and still is, displayed in them. Today, this is usually food colouring in water but originally chemicals, which were often dangerous, were used. The bright colours were not only intended to attract customers but also likely to represent certain things. For example blue and red may have represented venous (deoxygenated) and arterial (oxygenated) blood. The colour of the liquid could also represent chemical substances, for example yellow for gold, green for copper and purple for mercury.
Although the carboy is still a widely used symbol for pharmacists and some can still be found in shop windows, they are no longer a common sight and instead we see advertisements and the latest products.