JAMES BOSWELL, The Life of Samuel Johnson
The epigram, coming from another literary biography, might seem to have some significance to the relationship between Shade and Kinbote. Instead its relevance is to VN and Shade. The basis of the analogy is that of control of another creature's fate. Mr. Langton holds the fate of the city's cats under his finger, the way VN holds the fate of his characters, in this case Shade. Presumably VN was amused or bothered by criticism of how he treated his fictitious creatures. Johnson's reassurance of the fate of his own cat, Hodge, is then to be applied to Shade, i.e., Shade will not be shot. This should be taken as a clue against a naive reading of the novel in which Shade is indeed shot. Instead Shade loses his daughter; and then his sense of self when he metamorphoses into Kinbote; and then as Kinbote, presumably, does indeed take his own life by gunshot, after the novel is over.
ps. there is no intent to disparage anyone's particular reading in using the term naive. I simply mean a reading that takes Shade, Kinbote, New Wye, Zembla et al. as all, more or less, equally real within the confines of the novel.