Pauline Kael

"...But by the late thirties, despite her exquisite performances, films such as The Little Minister and Quality Street (which were not bad) had made her box-office poison. The public didn't want tremulous anguish in crinoline: James M. Barrie had his day, quaintness was out. Bringing Up Baby, Hepburn's first comedy, made in 1938, rescued her. [Other reports indicate that Baby did little at the time for Hepburn's career, other than, say, introducing her to Cary Grant.]

"Lunatic comedy of the thirties generally started with an heiress; this one starts with an heiress (Hepburn) who has a dog, George, and a leopard, Baby. Cary Grant is a paleontologist who has just acquired the bone he needs to complete his dinosaur skeleton. George steals the bone, Grant and Baby chase each other around, the dinosaur collapses--but Grant winds up with Hepburn, and no paleontologist ever got hold of a more beautiful set of bones.... [I]t's her best comedy."

Pauline Kael
Kiss Kiss Bang Bang (1968), p. 297-98