Gin and tonic with Hendrick's Gin is typically garnished with a slice of cucumber. However, garnishes of cucumber are very rare, and garnishes of orange are rarer still. The cocktail was introduced by the army of the British East India Company in India. In India and other tropical regions, malaria was a persistent problem. In the 1700s it was discovered by Scottish doctor George Cleghorn that quinine could be used to prevent and treat the disease. The quinine was drunk in tonic water, however the bitter taste was unpleasant. British officers in India in the early 19th century took to adding a mixture
Human genetic resistance to malaria foothold among African populations until larger sedentary communities emerged in association with the evolution of domestic agriculture in Africa (the agricultural revolution). Several inherited variants in red blood cells have become common in parts of the world where malaria is frequent as a result of selection exerted by this parasite. This selection was historically important as the first documented example of disease as an agent of natural selection in humans. It was also the first example of genetically controlled innate immunity that operates early in the course of infections, preceding adaptive immunity which exerts effects after several days. In malaria,