1. Edward Jenner developed a vaccine from cowpox.

2. From the discovery that harmless cowpox gave protection against deadly smallpox came vaccination and the end of smallpox as a scourge in the western world.

3. This is because the material in cowpox (a disease affecting the udders of cows), was injected into people to protect them against an attack of smallpox.

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

5. From the discovery that harmless cowpox gave protection against deadly smallpox came vaccination and the end of smallpox as a scourge in the Western world.

6. A vaccine prepared from the cowpox virus and inoculated against smallpox.

7. The discovery of the cowpox vaccination let the danger of vaccination more less, and cost lest.

8. 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.

9. In nineteen century, Enligh doctor Pearson came to Macao to spread the cowpox vaccination.

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

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

12. Variola virus belongs to the genus of orthopoxvirus, and there are some other infectious members, such as Vaccinia virus, cowpox virus, and monkeypox virus.

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