Devils Symbol
The two murderers are the devils that are mentioned in the title of the play, and they symbolize the devil because they are committing murder specifically to harvest bodies. They are also symbolic of the devilish act of tempting a good man into doing a bad thing.
Admiration for Doctors Motif
Doctors were held in a very high regard during this time and Dr Rock is very much admired and respected. He is asked to work a lot as a lecturer precisely because of this esteem. This is a motif in the play even at the end when the public loses respect for him; they are devastated by the seeming betrayal of a doctor whom they greatly admire. The change in public perception relates to the motif of the way in which doctors were revered.
Doctor Symbol
A doctor in the nineteenth century was also seen as someone that symbolized good, and also who symbolized what was right. This fact is anther reason for public horror over Rock's actions.
Burke and Hare Allegory
In 1882, William Burke and William Hare murdered sixteen people so that they could sell their bodies to medical professionals for research. This play is allegorical of this case. The men sold the bodies for anatomical dissection, and were sold to Robert Knox, an anatomist.
Dr Rock Allegory
Dr Rock is an allegory of real-life anatomist Dr Robert Knox, who purchased the corpses of murder victims and used them in his famed anatomical lectures in Scotland in the nineteenth century.
