Al-Razi (Rhazes)

He united medicine and chemistry: extracted sulphuric acid by early methods, prepared alcohol by distillation, and in Sirr al-Asrar classified substances into minerals, plants and animals with a clear taxonomy. In medicine he distinguished smallpox from measles in Al-Hawi, and was the first to propose choosing a hospital site by hanging meat in Baghdad's districts to find the purest air — on that basis the great bimaristan was built.