POSIDONIUS.—You say: “_Idque situm media regione in pectoris hæret._”—“The mind is in the middle of the breast.”—But, when you composed your beautiful verses, did you never make any effort of the head? When you speak of the orators Cicero and Mark Antony, do you not say that they had good heads? And were you to say that they had good breasts, would not people imagine that you were talking of their voice and lungs? LUCRETIUS.—Are you not convinced, from experience, that the feelings of joy, of sorrow, and of fear, are formed about the heart? _Hic exultat enim pavor ac metus; hæc loca circum Lætitiæ mulcent._ For there our passions live, our joy, our fear, And hope. Do you not feel your heart dilate or contract itself on the hearing of good or bad news? Is it not possessed of some secret springs of a yielding and elastic quality? This, therefore, must be the seat of the soul. POSIDONIUS.—There are two nerves which proceed from the brain, pass through the heart and stomach, reach to the parts of generation, and communicate motion to them; but would you therefore say, that the human mind resides in the parts of generation? LUCRETIUS.—No; I dare not say so. But though I should place the soul in the head, instead of placing it in the breast, my principles will still subsist: the soul will still be an infinitely subtile matter, resembling the elementary fire that animates the whole machine. POSIDONIUS.—And why do you imagine that a subtile matter can have thoughts and sentiments of itself? LUCRETIUS.—Because I experience it; because all the parts of my body, when touched, presently feel the impression; because this feeling is diffused through my whole machine; because it could not be diffused through it but by a matter of a very subtile nature, and of a very rapid motion; because I am a body, and one body cannot be affected but by another; because the interior part of my body could not be penetrated but by very small corpuscles; and, in consequence, my soul must be an assemblage of these corpuscles. POSIDONIUS.—We have already agreed, in our first colloquy, that it is extremely improbable that a rock could compose the “Iliad.” Will a ray of the sun be more capable of composing it? Suppose this ray a hundred thousand times more subtile and rapid than usual, will this light, or this tenuity of parts, produce thoughts and sentiments? LUCRETIUS.—Perhaps it may, when placed in organs properly prepared. POSIDONIUS.—You are perpetually reduced to your _perhaps_. Fire, of itself, is no more capable of thinking than ice. Should I suppose that it is fire that thinks, perceives, and wills in you, you would then be forced to acknowledge that it is not by its own virtue that it has either will, thought, or perception. LUCRETIUS.—No; these sensations will be produced not by its own virtue, but by the assemblage of the fire, and of my organs.