And I've already given you some clues about this, in that this process of vaccination that Jenner had developed was intentionally injecting into healthy patients, a microorganism.

我刚刚已经向你们提示了一些,在詹纳发明的接种过程里,故意把微生物注射到健康病人身上

耶鲁公开课 - 生物医学工程探索课程节选