One day a girl came to see him who had a cowpox sore on her hand.

一天一个女孩儿来看他，女孩儿手上有个牛痘疮。

Unlike Jenner's later vaccination, which used cowpox, variolation used a small measure of smallpox itself.

接种人痘，是直接使用小量的天花，和金纳后来用牛痘接种不同。

Jenner Edward, an Enligh doctor improved the vaccination to cowpox vaccination, and accomplished the second leap of vaccination.

在医生琴纳的研究下把人痘术改进成牛痘术，实现了种痘术的第二次飞跃。

Jimmy caught cowpox and soon got better, but later when he came near people who had smallpox he did not catch it, though other people die.

吉米感染了牛痘并且很快就痊愈了。后来，他接触天花患者却不被感染，即使有的人都因患天花而死去。

The vaccinated person developed antibodies which protected both against the cowpox infection and against the closely related virus that caused smallpox.

人在接过种后产生的抗体可以同时对牛痘病毒感染及其密切相关的天花病毒感染起到保护作用。