Percussion
a method of physical examination, performed by gently striking some part of the body-especially the chest or the abdomen-with the fingers or an instrument, to ascertain its healthy or diseased condition. Also in music, an ingenious contrivance whereby a hammer strikes the tongue of a reed and sets it (in motion simultaneously with the admission of air from the wind chest, thus securing the rapid speech of the reed. It is commonly used in cabinet organs, but has also been applied to the largest reeds of a church organ.