John snow was a famous doctoc in London-so expert,indeed,that he attended Queen Victoria as personal。 But he became inspired when he thought about helping ordinary people exposed to cholera。
This was the deadlly disease of its day。Neither its cause nor its cure was understood。So many thousands of terrified people died everytime there was an outbreak。
John Snow wanted to face the challenge and solve this problem。He knew that cholera would never be controlled until its cause was found。