18世纪末,英国著名医生琴纳忙于解决天花这个难题。他研究了许多病例,仍然没有找到可行的治疗办法。后来,他把思路放到了那些未染上此病的人身上,从挤奶女工手上提取微量牛痘疫苗,接种到一位8岁男孩的胳膊上。一个月后 At the end of the 18th century, the famous British doctor Jenner was busy solving the problem of smallpox. He studied many cases and still did not find a viable treatment. Later, he put his thoughts on those who had not contracted the disease, took a small amount of vaccinia vaccine from the hands of milking workers and inoculated the arm of an 8-year-old boy. A month later