Because it was in the 1950's or so, maybe the late 1940's, that people started to discover lithium, even though it had no natural function, it did do something in our bodies.

因为在二十世纪五十年代左右，可能是四十年代末期，人们开始发现锂，尽管不参与人体的正常生理活动，但是它确实会对我们的身体产生影响。

麻省理工公开课 - 化学原理课程节选

And so in the 1940s, a group of people led by Collier started to develop a large scale production method for making a reliable source of vaccinia virus.

在二十世纪四十年代,科利尔带领一群人开始研究,一种大规模的生产方法,这种方法能制得牛痘病毒的可靠来源

耶鲁公开课 - 生物医学工程探索课程节选