Had this excellent Man, Monseiur des Cartes, been half as conversant in Anatomy, as he seems to have been in Geometry, doubtless he would never have lodged so noble a guest as the Rational Soul in so incommodious a closet of the brain, as the Glandula Pinealis is; the use whereof hath been demonstrated to be no other but to receive into its spongy cavities, from two little nerves, a certain serous Excrement, and to exonerate the same again into its vein, which nature hath therefore made much larger than the artery that accompanieth it; and which having no communication with the external organs of the senses, cannot with any colour of reason be thought the part of the brain wherein the Soul exerciseth her principal faculties of judging and commanding.