Plotinos: Complete Works, v. 2 In Chronological Order,...

The vegetative power present in the whole body communicates to every part thereof a trace of the soul. It is therefore to the entire body that we must refer suffering, pleasure, and the desire of food. Though nothing definite is ascertained about the seat of sexual desire, let us grant that their seat is in the organs destined to its satisfaction. Further, be it granted that the liver is the seat of the soul's faculty of desire, because that organ is particularly the theatre of the activities of the vegetative power which impresses a trace of the soul on the body; and further, because it is from the liver that the action it exercises starts.