Now it is a well-known principle that all people bitten by poisonous creatures become dangerously ill when they see them... as it is written in medical books...[.] Doctors have already mentioned the empirical fact amongst the wonders of reproductions that if the urine of a person bitten by a mad dog is put in a glass receptacle... there will appear in that urine the likeness of the young of small dogs. -- Ramban on Num 21:9 (Chavel's translation)
My purpose here is not to mock the Ramban who was a man of his own time and can't be faulted for reflexively relying on unexamined, received wisdom. Instead, I note simply that he was pleased to cite "medical books" and "doctors" as his authorities; thus, he isn't claiming to have acquired medical knowledge via the study of Torah, but through consultations with the (mistaken) experts of his own time and place.
As an aside, I'm still waiting for someone to provide the famous Chazon Ish sketch.