Tobias' faithful dog is in the bottom-left hand corner. The composition is the same as that of an 18th-century etching (Wellcome Library no. 16385i and 20903i), though there are many differences. In the etching Tobit sits in a Savonarola chair, while in the painting he sits on a stone structure. In the painting the trees are more compact. In the painting a staircase and balustrade are shown leading to the house in the background, but they are absent in the etching. The etching shows a hat resting on a stool in the lower right corner, which is absent from the painting. There are also other differences
Bible, Apocrypha, Tobit 6-11. The angel had informed Tobias that smoke from cooking a piece of the heart of the fish will cure demonic possession, while the gall applied to the eyes will cure cataract (Tobit c. VI, vv. 8-9). Tobias applies the gall to the eyes of his father Tobit, whose sight is restored