In1816,aFrenchphysiciannamedReneLaennecwasconsultedbyabuxomyoungwomanevidentlylabouringunderaheartdisease.PuremodestymadeLaennechesitatetoputhiseardirectlyonthewoman'schest,andtheverysizeofthebreastswasalsoanobstacle.Nowhehadseenchildrenplayingwithlong,hollowsticks:theyheldtheireartooneendofthestickwhiletheoppositeendwasscratchedwithapinwithresultantamplificationofthetransmittedscratch.Inaburstofinspiration,herolledasheafofpapertightlyintoatube,placedoneendofthetubeovertheyoungwoman'sheart,andlistenedfromtheotherend.Hewasnotalittlepleasedatbeingabletohearthebeatingoftheheartwithgreaterclaritythanhehadeverdonebefore.
Later,Laennecbuiltahollowwoodencylinder,andnameditthestethoscope.
一八一六年，一個身材豐滿的年輕女郎到法國醫生勒內．雷奈克處求診，患的顯然是心臟病。雷奈克礙於禮儀，不敢隨便把耳朵貼向她胸脯，而那對大乳房也令聽診困難。雷奈克見過小孩子拿着空心長棒玩耍：他們把棒的一端置於耳朵，而用針刮擦另一端，刮擦聲傳到耳朵會更為響亮。他靈機一觸，把一捆紙緊緊捲成圓筒形，一端置於那女郎心臟位置，自己則在另一端聆聽，發覺心跳聲之清晰，還勝過他向來聽到的，不禁十分高興。
後來，他做了個空心木圓筒，名之為「聽診器」。
【附注】我國古代太醫為后妃看病，據說會「懸絲診脈」，以免肌膚接觸，和雷奈克的聽診器似乎異曲同工。