happy as a clam 的词源

“满足和高兴”，到1833年通常被认为是指这种软体动物在高潮时的心理状态，因为那时它们无法被挖掘和食用。不过，最早的用法并没有详细解释，也许这个概念本身就包含了自我满足。中世纪英语中有whole as a fish（或trout）这个表达，意思是“健康”（14世纪初）。Sad as a clam出现在1828年的一首幽默诗中。

I was asked "if I liked Lord Byron,"

  I was asked "if it wasn t a jam,"

I was told "I had grown romantic,"

  I was told I was sad as a clam ;

["Cassius," complaining of dull society in "New York Mirror and Ladies Gazette," March 1, attributed to "The Boston Statesman"]

有人问我“是否喜欢拜伦勋爵”，

  有人问我“这是否是个jam”，

有人说我“变得多愁善感”，

  有人说我像蛤蜊一样悲伤；

[“卡西乌斯”在《纽约镜报与女士公报》1831年3月1日的文章中抱怨乏味的社交生活，归因于《波士顿州人》]