John Snow was a/an ___ doctor in London who ___ Queen Victoria as her personal ___.But he also wanted to help those ordinary people who were ___ to cholera.The cause and the ___ of the disease were not understood.So John Snow wanted to face the ___ and solve this problem.He became interested in two theories that possibly explained hoe cholera killed people.The first suggested that cholera multiplied in the air.And the second suggested that people ___ this disease into their bodies with their meals.John Snow ___ that the second one was correct but he needed evidence.So he was ready to begin his ___ in 1854.As the disease spread quickly through poor ___,he began to gather information about the disease.