Categories new and old

I am going through the books and sorting wood block images into different categories. Sometimes this is difficult because I don't want to create a new category just for one image. So, my dilemma with Phrenology is do I put it into "human form / mythological character" or "anatomy / medical image."

If I go by today's standard, it is definately mythological... but in although controversal in the 1800s it was considered to be a "new science" therefore it would fall under medical image.

I kid. I know where the image should actually go, and it is not today's standards that I should be using.