An English physician, Edward Jenner, discovered that by inoculating a person with pustules from the pox infection of a cow, smallpox could be prevented.
一位英国医生爱德华•琴纳(Edward Jenner)，发现通过接种感染牛痘脓疱可以预防天花。
He found that they'd all contracted a similar but milder disease, cow pox, which vaccinated them against the deadly smallpox.
他发现他们都得过一种相似的但是温和的小病，牛痘，正是由于牛痘使得他们逃过了致死的天花。
应用推荐