
The White Girl was recorded as sold on 21 July 1894. It may have been Study for 'Harmony in Grey and Peach Colour' m0469, which dates from 1872/1874.
The White Girl is catalogued in MacDonald 1995 (cat. rais.) [more] (cat. no. 471).

The White Girl, whereabouts unknown

Study for 'Harmony in Grey and Peach Colour', Manchester City Art Gallery
Unknown, although, given the title, it is assumed it was a girl or young woman dressed in white.
Unknown. It is highly unlikely that it was a study of Joanna Hiffernan (b. ca 1843-d.1886) related to any of the 'White' portraits of her, such as Symphony in White, No. 1: The White Girl y038 or Symphony in White, No. 2: The Little White Girl y052.

Study for 'Harmony in Grey and Peach Colour', Manchester City Art Gallery
It may be Study for 'Harmony in Grey and Peach Colour' m0469, one of two studies for Harmony in Grey and Peach Colour y131.
In a letter to Whistler in 1895 (the year after the sale of the pastel 'The White Girl') E. G. Kennedy described a 'pastel of the Little White Girl' as lacking a face, but the pastel, though 'little', is unlikely to have been a study for Symphony in White, No. 2: The Little White Girl y052. 1
E. G. Kennedy mentioned to Whistler a 'pastel of the Little White Girl, which you are to "put a head on" (or face) for me.' 2 It is not known if Whistler did anything of the sort, but if it is indeed Study for 'Harmony in Grey and Peach Colour' m0469, then he did add a very faint face.
Kennedy suggested that Whistler should show it to Isaac Cook, jr (1867-1926), presumably in the hope of a sale, but nothing more is recorded of this suggestion. 3
SALE:
1: 16 July 1895, GUW #07256.
2: 16 July 1895, GUW #07256.
3: 16 July 1895, GUW #07256.