Gangrene illustration from the 1830s. Figs 1 and 2 (bottom and centre right) show gangrena senilis - discoloration of the toes at the beginning of the disease. Fig 3 (top left) shows gangrene of the toes. Fig 4 (top right) shows mortification of the skin and subjacent cellular tissue from an obstacle to the return of the venous blood in consequence of disease of the heart. Robert Carswell.