Rubuta ci gaba don wannan sakin layi - Lokacin da babban fashewa
ya faru a London a 1854, Dr. John Snow ya tattara bayanai game da lokuta daban-daban, musamman ma wurin da suke a Soho (Landan), ta amfani da sababbin hanyoyin nazarin sararin samaniya da kuma tuntuɓar masu tuntuɓar su don kammala cewa gurɓataccen ruwa shine mai ɗaukar cutar, kuma ya sami nasarar kashe tushen. Taswirar da ke tare da rahotonsa na 1855 ya nuna lokuta daban-daban, an ɗora su a kowane wuri na gida, a fili yana nuna maida hankali a kusa da Broad Street Pump da kuma gibba a wuraren da ke da sauran hanyoyin ruwa. Yanzu an yaba da taswirar a matsayin mai juyin juya hali; kodayake rawar da take takawa a cikin binciken kanta da tasirinsa kan sasanta muhawara kan dalilin cutar sau da yawa ana wuce gona da iri, ya cancanci a yaba wa hangen nesa na Snow cewa taswira ita ce mafi inganci kayan aiki don sadarwa da tsarin sararin samaniya na cutar.