And in particular, dairy maids, whose responsibility was to milk cows, and so they had a very intimate relationship with cattle, often didn't get disease.

特别是挤奶女工,她们的工作就是挤奶,她们与奶牛有紧密的关系,通常不会得天花

耶鲁公开课 - 生物医学工程探索课程节选