Proof from dissection

We only know, for certain that, in the majority of maniacal persons that have been opened after death, more or less organic injury of the brain has been discovered, and that the said organic injury seems to be, for the most part, the consequence of an inordinate determination of blood to the head, a fact of extreme importance in a curative point of view.

C***
Practical Observations on Insanity, p. 42.