- from CatholicCulture.org
An aspergillum is an instrument used by a priest or deacon to sprinkle holy water at a liturgy. The term comes from the Latin asperge, which means sprinkle – a reference to its primary use. It is most commonly used during the Easter season as a reminder of baptism, but can also be used at other liturgies such as Confirmation, at a funeral to sprinkle holy water on the casket, at a wedding to bless the wedding rings, or to bless sacramental such as ashes on Ash Wednesday or palms on Palm Sunday. Traditionally, the aspergillum has taken one of two forms: a brush that is dipped in holy water and shaken or a silver ball on a stick which often contains a sponge or reservoir to hold the holy water. In either case, the aspergillum must occasionally be dipped into the aspersorium, or holy water bucket. The practice of sprinkling the congregation with holy water is a reference to the Old Testament practice of sprinkling the people with the blood of the animals which have been sacrificed. Water and blood are used because of their life-giving properties and are a reference to the sacrifices by which we are healed, the animal sacrifice for the ancient Jews and Jesus’ sacrifice for Christians.