if there was some sort of chemical in the River Thames,

如果在泰晤士河里有某种化学物质
surely it would be infinitely diluted,

它完全会被稀释
and so how would it be possible that this chemical substance,

那么如果是化学物质
if that's what it was, was spreading the disease?

它是如何传播疾病的呢
So, there was a big debate about whether Snow was actually right.

所以斯诺是否正确的一直在争论
It was proved later in the century conclusively that he was.

后来被证明他确实是正确的
But it's important to realize that for a long time his writing

但我们要意识到在很长一段时间里
was very far from convincing the international medical profession.

他的作品都没有能够说服大部分医学界
That didn't happen until the 1880s and 1890s.

直到十九世纪八九十年代
Well, what were some of the factors

那么在霍乱传到欧洲的过程中
in the transmission of cholera in the West?

有哪些因素呢
We've talked about trade and the transport revolution.

我们谈到过贸易和交通革命