Descartes threw a cat out a window
According to at least one biography, René Descartes was driven to prove that humans had souls and animals didn’t. So, naturally, he threw a cat out of a window to demonstrate its lack of emotion and sensation.
In addition to throwing cats out of windows, he also performed a pre-Pavlov experiment on a dog. He whipped the dog repeatedly while a violin was playing. He discovered that, after a while, the sound of the violin was enough to frighten the dog. He also conducted more gruesome experiments. Once, he cut the end of the heart of a living dog. He jabbed his finger inside the dog to see if it pressed his finger.