It turns out you can use that for lots of things, you can use it to detect the presence of small amounts of chemicals anywhere.

可以将抗体用来做很多事情,可以用来检测,任意地方是否存在某种微量的化学物质

耶鲁公开课 - 生物医学工程探索课程节选

You detect the presence of your friend's soul through its affects on your friend's body.

你可以检测到你朋友的灵魂的存在,通过它对你朋友身体的影响。

耶鲁公开课 - 死亡课程节选