At the Tate Britain is this lovely Sargent. It would be a beautiful portrait but for the strange treatment of the the right arm on the young woman in the white silk dress. How unfortunate! Here is a detail
His obsession with a kind of anatomical perfection destroys the sense of reality by calling attention to the awkward handling of the poise. It makes her seem spastic. A shame, as the rest of the painting is so beautifully done. He is too fine painter to have allowed this to happen.