john snow a doctor ,attended queen victoria as her personal physician . but he was will to help ordinary people exposed to cholera . many peopie died everytime there wsa an breakout . he wanted to face the challenge and solve the problem . two theories caught his attention the first suggested that cholera multiplied in the air .the second suggested that people absorbed this disease into their bodies and the disease attacted the body .john snow suspected that the second was right but he need evidence . when another break hit london in 1854 ,he was ready to begin his enquiry and tried to get information . he found most of the deaths were near a water pump and the spread of the disease was water . with the evidence , he was able to announce that pulluted water carried the virus . after that , he suggested that he source of all the water supplies should be examined . finally , "king cholera" was defected.