Extreme pain, the head of Christ (left); Memory of love or ecstatic gaze (right), plate 24 from the album, The Mechanism of Human Facial Expression. Dated: 1854-1856. Dimensions: image: 22.3 ? 16 cm (8 3/4 ? 6 5/16 in.) mount: 40.2 ? 27.9 cm (15 13/1