From Gareth Smit's article in The New Yorker:
The Berg Collection's roughly two thousand linear feet of manuscripts and archival materials were donated to the library, in 1940, by two brothers, Henry W. and Albert A. Berg. The brothers, both doctors who lived on the Upper East Side, were avid collectors of English and American literature—and of literary paraphernalia.
The library categorizes these items as "Realia"—objects from everyday life. The Berg Collection includes Charlotte Brontë's writing desk, with a lock of her hair inside; trinkets belonging to Jack Kerouac, including his harmonicas, and a card upon which he wrote "blood" in his own blood; typewriters belonging to S. J. Perelman and Paul Metcalf; Mark Twain's pen and wire-rimmed glasses; Vladimir Nabokov's butterfly drawings; and the death masks of the poets James Merrill and E. E. Cummings.
Although the Berg Collection is intended to cater to researchers, curators are always keeping an eye out for items that complement the existing archive. Virginia Woolf's cane may be of little interest to scholars, but it's an important artifact that was likely the last thing she used before her death.