Generally made of skins of animals; the head and legs being cut off, the skin was removed from the body without further cutting, and was then tanned by means of oak-bark. If wine fermented in a bottle of this kind, it would stretch the skin to such an extent that it could never be used for the purpose a second time; hence the lesson drawn by our Lord in Matt. 9: 17; Mark 2: 22; Luke 5: 37; cf. Job 32: 19.