"For this, O dearly beloved, is the genuine Christine": as Gifford notes, these words imitate the Catholic priest’s action of presenting the consecrated host to the congregation—an action which itself recapitulates Jesus’ words at the Last Supper (“This is my body . . . This is my blood”). He goes on to observe that the mocking substitution of “Christine” for Christ briefly makes Mulligan’s ceremony a Satanic black mass, since this inverted mass is traditionally celebrated over a woman’s naked body.
On his website of the occult, Donald Tyson describes the supposed practice thus:
The notorious black mass was supposedly a blasphemous parody of the Catholic mass celebrated by witches or sorcerers for the purpose of defiling the most holy beliefs and practices of the Church, and thereby pleasing the Devil, who would as a reward grant to them the power to do evil. Some of its infamous features include a defrocked priest who celebrated the mass on the belly of a naked woman, and the substitution of semen for the holy chrism oil, urine for the wine, and blackened turnip or excrement for the host. During the course of the mass, the defrocked priest was said to copulate with the woman serving as the altar. Sometimes the priest inserted holy wafers into the vagina of the woman before copulation. Sometimes the copulation was anal. The words of the ritual were read backwards or distorted by replacing “God” with “Devil” or “Satan.” The sign of the cross was made backwards. (http://www.donaldtyson.com)
Tyson notes that such events were “a fantasy created by the priests of the Inquisition as the worst thing they could possibly accuse supposed witches of doing.” Various eighteenth and nineteenth century decadents, however, read literary accounts of these supposed perversities and were inspired to stage their own enactments. For further reading, Tyson recommends H. T. F. Rhodes’ The Satanic Mass (1954).
In Circe, the black mass so glancingly evoked by Mulligan’s words receives elaborate stage direction:
On an eminence, the centre of the earth, rises the field altar of Saint Barbara. Black candles rise from its gospel and epistle horns. From the high barbicans of the tower two shafts of light fall on the smokepalled altarstone. On the altarstone Mrs Mina Purefoy, goddess of unreason, lies naked, fettered, a chalice resting on her swollen belly. Father Malachi O’Flynn, in a long petticoat and reversed chasuble, his two left feet back to the front, celebrates camp mass. The Reverend Mr Hugh C. Haines Love M.A. in a plain cassock and mortar board, his head and collar back to the front, holds over the celebrant’s head an open umbrella.This scene recycles many details of the Martello tower scene: eminence (top of the tower), center of the earth (omphalos), barbicans, shafts of light, smokepalled altarstone (hearth), chalice (shaving bowl), petticoat (dressinggown), celebrant (Mulligan), server (Haines). After the scene is set, Father Malachi chants a demonic inversion of Mulligan’s earlier “Introibo ad altare Dei”: “Introibo ad altare diaboli.” The Reverend Mr Haines Love (i.e., Hate-Love) then perverts the responsory line “To God who gladdens my youth,” by chanting “To the devil which hath made glad my young days.”