happy as a clam 的詞源

「心滿意足，心情愉快」，這個表達出現在1833年，通常被認為是指在高潮時期，貝類動物因無法被挖掘而食用時的心理狀態。不過，最早的用法並沒有詳細說明，或許這個概念本身就是一種自我滿足。中古英語中曾用whole as a fish（或trout）來表示「健康」（14世紀初）。Sad as a clam則記錄於1828年的一首諷刺詩中。

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"]

有人問我「喜不喜歡拜倫勳爵，」

  有人問我「這不是一場jam，」

有人告訴我「我變得浪漫了，」

  有人告訴我我「悲傷得像一隻蛤蜊；」

[「卡西烏斯」在《紐約鏡報與淑女公報》1831年3月1日中，抱怨乏味的社交生活，該文被歸於《波士頓國士報》]