A colleague of mine studied physiology and anatomy at McGill University likely in the 1970s. She said the cadavers were mainly unclaimed bodies of homeless people from the city of Montreal. The rule was that all work was to be done in the university labs, but she said students often snuck body parts out to conduct dissection work after hours in their dorm rooms. A lot has changed in the field, but it wasn't that long ago that we treated the dead like a tool.