<ref>"He demonstrated that cholera is communicated by contaminated water, and he made the art of anaesthesia a science." [http://www.general-anaesthesia.com/images/john-snow.html]</ref> | <ref>"He demonstrated that cholera is communicated by contaminated water, and he made the art of anaesthesia a science." [http://www.general-anaesthesia.com/images/john-snow.html]</ref> |