Yet fancy not its nature simple so. For an impalpable aura, mixed with heat, Deserts the dying, and heat draws off the air; And heat there's none, unless commixed with air: For, since the nature of all heat is rare, Athrough it many seeds of air must move. Thus nature of mind is triple; yet those all Suffice not for creating sense--since mind Accepteth not that aught of these can cause Sense-bearing motions, and much less the thoughts A man revolves in mind. So unto these Must added be a somewhat, and a fourth; That somewhat's altogether void of name; Than which existeth naught more mobile, naught More an impalpable, of elements More small and smooth and round. That first transmits Sense-bearing motions through the frame, for that Is roused the first, composed of little shapes; Thence heat and viewless force of wind take up The motions, and thence air, and thence all things Are put in motion; the blood is strook, and then The vitals all begin to feel, and last To bones and marrow the sensation comes-- Pleasure or torment. Nor will pain for naught Enter so far, nor a sharp ill seep through, But all things be perturbed to that degree That room for life will fail, and parts of soul Will scatter through the body's every pore. Yet as a rule, almost upon the skin These motion aIl are stopped, and this is why We have the power to retain our life.