Philosophers and psychologists knew for a long time that getting smacked in the head could change your mental faculties; that diseases like syphilis could make you deranged; that chemicals like caffeine and alcohol can affect how you think.

哲学家和心理学家在很久以前便知道,头部受到重创,会改变你的心理官能,像梅毒这样的疾病可以让你精神错乱,像咖啡因和酒精这样的化学药品,可以影响到你的思维

耶鲁公开课 - 心理学导论课程节选

So if you're working with cyanide in the lab as potassium cyanide or sodium cyanide, those are what are called p h s's, it's a rating for different kinds of chemicals.

因此如果你在实验室中,需要用到氰化物，比如氰化钾或者氰化钠，这就是所谓的，“P，H，S“,这是化学药品有害程度的一个级别。

麻省理工公开课 - 化学原理课程节选