If you wanna know whats on the inside you have to cut it open, this means that someone cut open another human to find out what was inside, and if we take into account that history can be lost, there was more then one person who did this. also we can't safely say they did this to a person who was already dead, they could of done it while the subject was alive or killed someone to have a body to cut open. we also have to ask ourselves who would listen to a man who just randomly cut a human open and explained what was inside? when you think about it, this really shows how many inhumane people had to do bad things so we could have the information of the human body that we do now.