Hundreds of theories exist concerning the identity of “Jack the Ripper”. His propensity for anatomical dissection with a knife—and in particular the rapid location and removal of specific organs—led some to speculate that he must have been surgically trained. However, re-examination of a mortuary sketch of one of his victims has revealed several aspects of incisional technique highly inconsistent with professional surgical training. Related discrepancies are also apparent in the language used within the only letter from Jack considered to be probably authentic. The techniques he used to dispatch his victims and retrieve their organs were, however, highly consistent with techniques used within the slaughterhouses of the day. East London in the 1880s had a large number of small-scale slaughterhouses, within which conditions for both animals and workers were exceedingly harsh. Modern sociological research has highlighted the clear links between the infliction of violence on animals and that inflicted on humans, as well as increased risks of violent crimes in communities surrounding slaughterhouses. Conditions within modern slaughterhouses are more humane in some ways but more desensitising in others. The implications for modern animal slaughtering, and our social reliance on slaughterhouses, are explored.