There was no "Dlugacz" on Dorset Street in 1904. Every other shopowner in Ulysses appears in the 1905 Thom's Directory, but Joyce named the butcher after a Jewish intellectual whom he knew in Trieste, because of the Zionism that Dlugacz passionately espoused. When Bloom infers in Calypso that the butcher is Jewish ("I thought he was"), and sees that the recognition is mutual, he appears to feel drawn to the man but saves his greeting for another day. Later in the chapter he dismisses Dlugacz's Zionism with the thought, "Enthusiast."
Like another Jewish intellectual, Ettore Schmitz (Italo Svevo), Moses Dlugacz (1884-1943) was one of Joyce's students at the Berlitz school in Trieste. In The Jews of Ireland, Louis Hyman notes that the two men "had a common interest in literature and etymology, music and philosophy. The son and grandson of Ukrainian rabbis and himself an ordained rabbi in his fifteenth year, Dlugacz became Joyce's pupil in English on his appointment in 1912 to the post of chief cashier in the local Cunard Line office" (184). When war broke out in 1914, he lost his Cunard position and opened a small grocery store and wholesale food business.
Hyman observes that "Dlugacz tried to win over to the Zionist cause all Jews and Gentiles with whom he came in contact; no doubt he tried to make a convert of Joyce, who, discussing the Irish revival with Padraic Colum in 1903, remarked contemptuously 'I dislike all enthusiasms,' and who seems, in this instance, too, to have remained unsympathetic. Dlugacz organised and voluntarily directed courses in Hebrew and Jewish history for the Triestine Jewish youth, and perhaps gave Hebrew lessons to Joyce, who is reported to have studied the language" (184). Several years later, Dlugacz began promoting emigration to Palestine, and in 1921 he attended the twelfth Zionist Congress in Carlsbad (185).
When Bloom pays for his kidney, having stood for some time reading a Zionist ad with obvious interest, the gaze of the "ferreteyed porkbutcher" communicates recognition that Bloom too may be Jewish: "A speck of eager fire from foxeyes thanked him. He withdrew his gaze after an instant. No: better not: another time." Bloom declines to initiate ethnic camaraderie, and after reading the Agendath Netaim ad he thinks, "Nothing doing." By making his butcher deal in pork, and having him wrap this unclean meat in pages promoting a Zionist settlement, Joyce compounds Bloom's lack of piety and "enthusiasm" with some of his own. Nevertheless, the meeting with Dlugacz sets Bloom's mind off on a chain of reflections on old Jewish friends, old Jewish texts, and the ancient Jewish people. His ancestral homeland clearly calls to him, and the allure of Zion will recur regularly in Ulysses as one aspect of the book's symbolic concern with home rule.