Murder was a subject about which Dadd knew a good deal, but in depicting it for the ‘Passions’ series he has chosen to use the archetypal story of Cain and Abel, which requires no specialist knowledge. Since he never regarded his own act of killing as murder, perhaps it is not surprising that he failed to show it here (though it seems to have been in his mind when he painted ‘Hatred’); but among his fellow patients there were several whose stories could have been used if he had wished to make this a scene from modern life. In fact Dadd seems never to have drawn on the Bethlem or Broadmoor environment for subject matter, preferring his own imagination and the artistic themes and influences which he had brought with him from the world outside.