John Snow was a famous doctor in London — so expert, indeed, that he 【小题1】 Queen Victoria as her personal physician. But he became inspired when he thought about helping ordinary people 【小题2】 to cholera.

The first suggested that cholera multiplied in the air, a cloud of dangerous gas floated around until it found its 【小题3】.

Cholera used to be one of the most feared diseases in the world, until a British doctor, John Snow, showed how it could be o【小题1】. This illness causes s【小题2】diarrhea, dehydration, and even death. In the early 19th century, when an outbreak of cholera hit Europe, millions of people died from the disease. As a young doctor, John Snow became f【小题3】, because no one knew how to prevent or treat cholera. In time, he rose to become a famous doctor, and even a【小题4】to Queen Victoria when she gave birth. However, he never lost this d【小题5】to destroy cholera once and for all.

In general, doctors in those days had two c【小题6】theories to explain how cholera spread. One theory was that bad air caused the disease. Another was that cholera was caused by an i 【小题7】 from germs in food or water. Snow s 【小题8】 to the second theory. It was correct, but he still needed p【小题9】. Consequently, when an outbreak of cholera hit London in 1854, Snow began to investigate. He discovered that in two particular streets the cholera outbreak was so severe that more than 500 people died in ten days. He was d【小题10】 to find out why.