He appears to have first used the Latin word fomes, meaning tinder, in the sense of infectious agent, in his essay on contagion De Contagione et Contagiosis Morbis, published in 1546: "I call fomites [from the Latin fomes, meaning "tinder"] such things as clothes, linen, etc., which although not themselves corrupt, can nevertheless foster the essential seeds of the contagion and thus cause infection.". His theory remained influential for nearly three centuries, before being superseded by a fully developed germ theory.