Pauline Kael

"Katharine Hepburn gives an inspired performance as willful Jo; she has a joyous tomboy abandon when she first enters Laurie's mansion-like home, and cries out, "What richness!" She strikes absurdly romantic poses, and they're enchanting...."

Pauline Kael
5001 Nights at the Movies (1984?), p. 333

See also Kael's calling Hepburn "a magnificent Jo" in, I think, her notes on Bringing Up... in Kiss Kiss Bang Bang (1968), and her saying something like, "Apart from her comedies, Katharine Hepburn had been best in Little Women, Alice Adams, and later in her career, in Long Day's Journey Into Night, also somewhere in Kiss Kiss Bang Bang.