He distinguishes between a “sensible rapture” (sinnliche Wollust) and an emotion because the former begins in a part of a body, that is, with an actual external perception, while the latter “arises in the brain itself,” but in either case the feeling of the pleasure “arrange[s] the fibers of the brain into an appropriate tone, employing them without fatiguing them,” and then “The brain communicates this harmonious tension to nerves of the other parts of the body and the body becomes comfortable”