What was the most common way to find out Brain Function in History? Name an Example

-To study people with Brain Damage, as if part of a Brain is Damaged, and one of the Body's Stop Responding, a Link could be Established -Example could be Paul Broca [1824-1880] He found out the Broca Area, which is all about Language. He did Experiments with people that had Speech Problems, and he found out All of them had Lesions on the Broca Area [Lesions are Wounds, tumors etc...] -This was a Massive Discovery, which would open the door to this Science