Beyond Good and Evil by Friedrich Nietzsche Chapter 2 Page 10

consequently also, a good deal more silent. It happens more frequently, as has been hinted, that a scientific head is placed on an ape’s body, a fine exceptional understanding in a base soul, an occurrence by no means rare, especially among doctors and moral physiologists.

And whenever anyone speaks without bitterness, or rather quite innocently, of man as a belly with two requirements, and a head with one; whenever any one sees, seeks, and WANTS to see only hunger, sexual instinct, and vanity as the real and only motives of human actions; in short, when any one speaks “badly” — and not even “ill” — of man, then ought the lover of knowledge to hearken attentively and diligently; he ought, in general, to have an open ear wherever there is talk without indignation.