JohnSnowwasbornandworkedasa__36__inGreatBritain．Exactlyhewasananaesthetist，37 meansthatheputpeopletosleepduringoperation．Healsobegantoexperimentusingthesamedrugstohelpwomenwhentheyhad 38 ．Thatiswhyhebecamethedoctorwho 39 Queenvictoriatogivethebirthofherbabies．
Atthetimehelived，cholerawasthemost 40disease．Neitheritscause，norits 41 wasunderstood．Somanythousandsofpeopledied 42 therewasanoutbreak．JohnSnowwas 43tohelpordinarypeople 44 fromcholera．He 45 thediseasebeganinthestomachandthepatientsdiedquicklyafterseverevomiting(呕吐)anddiarrhea(腹泄)．46 ，hebelievedcholeraresultedfromwater．Whenanother 47 hitLondonin1854，JohnSnowsettowork．
JohnSnowapproachedtheprobleminasystematicway．Hemarkedonamap 48 allthedeadpeoplehadlivedandfoundmanyofthe 49 werenearawaterpump．Itseemedthewaterwasthe 50 ．Sohecollectedinformationaboutthe 51habitsofthedeadpeopleandusedthemeventuallytoprovehistheory．Withtheinformation 52 ，JohnSnowwassure that 53 waterwasthecause．
Thenpeoplewererequiredto54 thewatercompanytosupplythemwithcleanwater．Thanks__55___JohnSnowtherewasnomoreoutbreaksofcholera．
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