Interestingly enough, you can tell how much quinine is in your gin and tonic by placing it under a black light. So, if you've ever been in a dark bar or nightclub and seen people with glowing ...

In order to make the bitter quinine more palatable, they mixed it with gin, creating the gin and tonic. When a black light is shone on it, the quinine emits a captivating blue glow, making tonic ...