A matrass (mod. Latin matracium) is a glass vessel with a round or oval body and a long narrow neck, used in chemistry as a digester or distiller. The Florence flask of commerce is frequently used for this purpose. The word is possibly identical with an old name matrass ( Fr. materas, matelas) for the bolt or quarrel of a cross-bow. If so, some identity of shape is the reason for the application of the word; bolthead is also used as a name for the vessel. Another connection is suggested with the Arabic matra, a leather bottle.