[ Disraeli / Vivian Grey ]
Newfoundlands are referenced four times in this novel, all in one early scence in which Vivian Grey (who is a man, btw) meets Mr. Cleveland, a man who will become his business partner.
Mr. Cleveland was tall and distinguished, with a face which might have been a model for manly beauty. He came forward to receive Vivian with a Newfoundland dog on one side and a large black greyhound on the other; and the two animals, after having elaborately examined the stranger, divided between them the luxuries of the rug.
. . . .
Vivian had, unbidden, seated himself by the side of Mr. Cleveland's library table; and, not knowing exactly how to proceed, was employing himself by making a calculation whether there were more black than white spots on the body of the old Newfoundland, who was now apparently happily slumbering.
"Well, sir!" continued the Newfoundland's master, "the nature of your communication? I am fond of coming to the point."
. . . .
"The Marquess of Carabas!" almost shrieked Mr. Cleveland, as be started from his seat and paced the room with hurried steps; and the greyhound and the Newfoundland jumped up from the rug, shook themselves, growled, and then imitated their master in promenading the apartment, but with more dignified and stately paces.
Disraeli published a sequel to Vivian Grey the following year; it apparently was published with the same title and included the original novel, so it is more like an expansion of the novel than a separate sequel.
There's one additional mention of a Newfoundland in this new material:
Miss Von Spittergen and Vivian crossed a dyke from the plantation, and immediately passing through a large white wooden gate, with two hideous griffons grinning on the top of it, Marcus Aurelius dashed up to the stable door, followed by Max. They were instantly saluted by an immense Newfoundland, whose joyous bark was answered by a responsive neigh from his companions of the stable; and in an instant, Triton was scrambling up Marcus Aurelius, for the pleasure of biting Miss Von Spittergen's silver buttons, and licking her face with his great red tongue.
"Down — down, Triton!"
Triton obeyed very willingly, but turning round, felt himself greatly consoled for his rebuff, by seeing that he had to welcome a visitor. He flew up at Max's neck. The princely pet, unused to such rude embraces, showed certain signs of exclusiveness, which made Vivian exercise his whip across master Triton's back; who, in his turn, was equally irate at this unusual and ungrateful reception of his caresses. The dog slunk from under Vivian's lash, and springing up behind Max, made him give a sudden and violent kick, which sent Vivian, unprepared as he was, head foremost into some low, thick bushes of bow, which had been planted to screen a pig-sty.