The Gin and Tonic was created not for pleasure, but for survival. In the early 19th century, British officers and soldiers stationed in India faced the constant threat of malaria. Quinine, derived from the bark of the cinchona tree, was a known preventative, but its bitter taste was nearly unbearable. To make the medicine more palatable, the soldiers began mixing the quinine with water, sugar, lime, and gin. This 'tonic water' effectively masked the bitterness while providing a refreshing drink in the tropical heat. Over time, the quinine content in commercial tonic water was significantly reduced, but the combination remained a classic. Today, tonic water still glows blue under ultraviolet light due to the presence of residual quinine.