_Sight_.] Of these five senses, sight is held to be most precious, and the best, and that by reason of his object, it sees the whole body at once. By it we learn, and discern all things, a sense most excellent for use: to the sight three things are required; the object, the organ, and the medium. The object in general is visible, or that which is to be seen, as colours, and all shining bodies. The medium is the illumination of the air, which comes from [983]light, commonly called diaphanum; for in dark we cannot see. The organ is the eye, and chiefly the apple of it, which by those optic nerves, concurring both in one, conveys the sight to the common sense. Between the organ and object a true distance is required, that it be not too near, or too far off! Many excellent questions appertain to this sense, discussed by philosophers: as whether this sight be caused intra mittendo, vel extra mittendo, &c., by receiving in the visible species, or sending of them out, which [984]Plato, [985]Plutarch, [986]Macrobius, [987]Lactantius and others dispute. And, besides, it is the subject of the perspectives, of which Alhazen the Arabian, Vitellio, Roger Bacon, Baptista Porta, Guidus Ubaldus, Aquilonius, &c., have written whole volumes. _Hearing_.] Hearing, a most excellent outward sense, by which we learn and get knowledge. His object is sound, or that which is heard; the medium, air; organ, the ear. To the sound, which is a collision of the air, three things are required; a body to strike, as the hand of a musician; the body struck, which must be solid and able to resist; as a bell, lute-string, not wool, or sponge; the medium, the air; which is inward, or outward; the outward being struck or collided by a solid body, still strikes the next air, until it come to that inward natural air, which as an exquisite organ is contained in a little skin formed like a drum-head, and struck upon by certain small instruments like drum-sticks, conveys the sound by a pair of nerves, appropriated to that use, to the common sense, as to a judge of sounds. There is great variety and much delight in them; for the knowledge of which, consult with Boethius and other musicians. _Smelling_.] Smelling is an outward sense, which apprehends by the nostrils drawing in air; and of all the rest it is the weakest sense in men. The organ in the nose, or two small hollow pieces of flesh a little above it: the medium the air to men, as water to fish: the object, smell, arising from a mixed body resolved, which, whether it be a quality, fume, vapour, or exhalation, I will not now dispute, or of their differences, and how they are caused. This sense is an organ of health, as sight and hearing, saith [988]Agellius, are of discipline; and that by avoiding bad smells, as by choosing good, which do as much alter and affect the body many times, as diet itself. _Taste_.] Taste, a necessary sense, which perceives all savours by the tongue and palate, and that by means of a thin spittle, or watery