Few details in Ulysses are more cryptic than the tuber that Bloom makes sure is in his pants before heading out for the day: "Potato I have." Eleven chapters later, readers finally gain some sense of its provenance and purpose. Medical, familial, historical, sexual, and literary associations attach to the potato in Circe, identifying it as an object that holds talismanic power for Bloom, as well as sentimental value. In Nausicaa, a seemingly unrelated thought about Jewish religious observance also sheds light. But none of this polysemous significance could possibly be inferred initially.
On first encountering the potato in Calypso, perhaps the only plausible inference to draw is that, given the Irish context, it may have something to do with the Great Hunger. Bloom does think of the "potato blight" in Lestrygonians, and at the end of that chapter he notices his personal potato again as he searches for his lemon soap: "Try all pockets. Handker. Freeman.Where did I? Ah, yes. Trousers. Potato. Purse. Where?"
But when the object next surfaces at the end of Oxen of the Sun, someone, somehow, apparently has noticed Bloom's possession and infers that he carries it as a prophylactic: "Sir? Spud again the rheumatiz?" When the potato reappears early in the next chapter, Circe, this impression is confirmed. After Bloom is nearly run down by a tram, he reaches instinctively for the potato: "(He feels his trouser pocket.) Poor mamma's panacea."
So the potato is a talisman or home remedy, and Bloom's mother, Ellen Higgins Bloom, gave it to him. Not long later, she shows up to save him from danger and reenacts the donation: "O blessed Redeemer, what have they done to him! My smelling salts! (She hauls up a reef of skirt and ransacks the pouch of her striped blay petticoat. A phial, an Agnus Dei, a shrivelled potato and a celluloid doll fall out.) Sacred Heart of Mary, where were you at all, at all?"
As Bloom says to Zoe later in the chapter, the potato is "A talisman. Heirloom." He tells her, "Sir Walter Raleigh brought from the new world that potato and that weed [tobacco], the one a killer of pestilence by absorption, the other a poisoner of the ear, eye, heart, memory, will, understanding, all." Asking her to return it to him, he says, "(With feeling.) It is nothing, but still, a relic of poor mamma." At the end of the long hallucinatory passage introduced by the mention of Sir Walter Raleigh and tobacco, when Bloom is burned at the stake, the Daughters of Erin invoke the "Potato Preservative against Plague and Pestilence."
In "Faith and Betrayal: The Potato in Ulysses" (JJQ 28.1 : 269-76), Robert Merritt cites several relevant findings from Redcliffe N. Salaman's The History and Social Influence of the Potato (Cambridge UP, 1949, rpt. 1985). For many peasants in Ireland and other countries, Salaman writes, "A dried tuber carried in the pocket, or suspended from the neck, is a sure protection against rheumatism. / A 'pealed' potato, if carried in the pocket of the same side as an aching tooth, will cure the latter as soon as it itself is reduced to crumbs" (118).
Salaman also observes that the Spanish conquistadores called the potato a turma de tierra or earth-testicle, perhaps prompted by "the Aymara name choque which it is claimed stood equally for a potato tuber or a testicle" (129). While Joyce clearly knows something of the history of the potato's importation from the New World, it seems incredible to suppose that he would have known of this etymological link with testicles. Nevertheless, Circe unmistakably makes the association. Zoe discovers the potato when she passes her hand over Bloom's pants to caress his cock: "Has little mousey any tickles tonight? . . . How's the nuts?" As Bloom blathers about which side his gonads hang toward, she feels something hard and, concerned that it is a syphilitic "chancre," reaches "into his left trouser pocket and brings out a hard black shrivelled potato," and "puts the potato greedily into a pocket."
When Bloom eventually persuades Zoe to return what she has taken, "She hauls up a reef of her slip, revealing her bare thigh, and unrolls the potato from the top of her stocking." As Merritt observes, "The potato as a surrogate for Bloom has passed from his groin to hers and back again, symbolically performing the rite of sexual intercourse" (273). This sexual exchange with Zoe clearly extends a circle of connections that began with Bloom's mother, because she too, like Zoe, "hauls up a reef of skirt" to give Bloom the potato. And Zoe's last name, of course, is . . . Higgins. The strong linguistic links between Ellen and Zoe, and their mutual circulation of the potato through Bloom, may say something about the Oedipal origins of his sexual desires. Alternatively, one might suppose that Ellen's gift protects him from the Circean allure of the prostitutes.
Many Joyceans have observed that the potato in Circe seems to stand in for the sprig of moly that enables Odysseus to resist Circe's spells. Although Bloom differs from his epic prototype in temporarily losing his protective plant, the analogy does seem relevant, because he regains the potato just as he regains his manhood: he breaks the spell of the Nymph, rebukes Bella, takes the potato back from Zoe, and then makes sure that Stephen is not cheated of his money, earning Bella's admiration. This Homeric association adds to the many suggestions that the potato holds some kind of power to ward off evil or disease.
Finally, Joyce curiously tucked into a distant chapter of his novel a reference to Jewish religious ritual that, if a reader should ever spot the connection, would make the initial mention of the potato in Calypso more suggestive of talismanic potency. In Nausicaa Bloom is pondering the dangers of seafaring (as befits his Odyssean role in that chapter), and thinks of lucky charms: "Off he sails with a scapular or a medal on him for luck. Well. And the tephilim no what's this they call it poor papa's father had on his door to touch." As happens so often with his attempts to recall past learning, Bloom gets the word tephilim wrong, and knows it, though he is thinking of something very similar. A mezuzah is a decorated case containing verses from Deuteronomy that is affixed to the right-hand front doorpost of a Jewish home (and sometimes to the frame of every room in a house). The mezuzah functions as an amulet to ward off evil. And where did Bloom touch his potato in Calypso? "On the doorstep" of his house, before reaching back to pull the door shut behind him.
Of such incredibly fine, endlessly involuted patterning, Hugh Kenner has this to say: "this, assuming even that we possess the lore and have the luck to make the connection, is not something we might hope to think of when we first read of how Bloom crossed his threshold and said 'Potato I have,' because at that time we have some hundreds of pages to traverse before the meaning of 'potato' will have been disclosed. Nor, when we know the meaning, does it work retroactively, since by then we have surely forgotten the doorframe adjacent to the initial 'Potato I have.' . . . Joyce's strange book has no stranger aspect than this, that no one comprehensive reading is thinkable. . . . Ulysses is so designed that new readers, given, even, what cannot be postulated, ideal immunity to attention overload, cannot possibly grasp certain elements because of a warp in the order of presentation, and veteran readers will perceive after twenty years new lights going on as a consequence of a question they have only just thought to ask. Such a question would be: Why is Bloom made to advert to the potato just when he does, on a page where there seems no earthly reason for him to remember the potato or for us to be apprised of it? And when we think to ask something happens" (Ulysses, 80).