The Gentleman's Magazine was an important and influential monthly magazine in the 18th and 19th Centuries; it began in 1731, ceased regular publication in 1907, and shut down completely in 1922.
The November, 1881, issue carried a reminiscence of Charles Dickens, who had died eleven years earlier, entitled "Charles Dickens at Home." The essay is anonymous although the author does claim "a particular friendship" with Dickens, and he recounts a number of personal anecdotes regarding Dickens' hospitality — and his dogs. (We know from other sources that the author of this reminiscence was the Anglo-Irish novelist, painter, lawyer, and Dickens friend Percy Fitzgerald.)
Dickens owned several Newfoundlands during his lifetime, along with many other dogs. As this author writes, Dickens "appreciated dogs, and understood their ways and fine nature better than anyone. . . ." (567)
The only reference to Dickens' Newfoundlands occurs as the author is writing about a dog he personally gave to Dickens, a Spanish mastiff named "Sultan" who proved to be a not particularly friendly dog to anyone or anything except Dickens himself; Dickens has to take him out muzzled, and he still gets into a lot of trouble, eating one of the Dickens family kittens, knocking down a soldier while out for a walk (Sultan seemed to hate anyone in a uniform), and on another occasion getting free and runnning wild for a while, coming home "covered with blood" even though he was still muzzled. The author of this article quotes a letter written to him by Dickens regarding this mastiff and his relationship with one of Dickens' Newfoundlands:
"A friend," he wrote on another occasion, "has sent me from America a thoroughbred young black Newfoundland dog since you were here. Sultan (who hates him mortally), Linda, I, and three or four small dogs, with the nature of canine parasites and toadies, make a show in the lanes and woods which I specially beseech you to come and see." (568)
Sultan met a not-particularly-unexpected fate: one day he got loose and grabbed a child by the leg; although the child was not seriously injured, Dickens had the mastiff shot.
There are no further mentions of Dickens' Newfoundlands.