“People called cancer the wolf, because it ‘ate up’ the person.” But this wasn’t just a linguistic quirk. The idea was actually translated into practice. “Some doctors would even apply raw meat to a cancerous ulcer, so that the wolf could feast on that for a while instead of ‘eating’ the patient.
Source
I could see how people 400 years ago could think that makes sense.
“There are two wolves inside of you. I’m afraid it’s terminal.”