On the nature of things (books 1 - 3)   

'Twould go, if once compacted as a pellet:
When death's unvexed repose gets hold on man
And mind and soul retire, thou markest there
From the whole body nothing ta'en in form,
Nothing in weight. Death grants ye everything,
But vital sense and exhalation hot.
Thus soul entire must be of smallmost seeds,
Twined through the veins, the vitals, and the thews,
Seeing that, when 'tis from whole body gone,
The outward figuration of the limbs
Is unimpaired and weight fails not a whit.
Just so, when vanished the bouquet of wine,
Or when an unguent's perfume delicate
Into the winds away departs, or when
From any body savour's gone, yet still
The thing itself seems minished naught to eyes,
Thereby, nor aught abstracted from its weight-
No marvel, because seeds many and minute
Produce the savours and the redolence
In the whole body of the things. And so,
Again, again, nature of mind and soul
'Tis thine to know created is of seeds
The tiniest ever, since at flying-forth
It beareth nothing of the weight away.
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.

Now in my eagerness to tell thee how
They are commixed, through what unions fit
They function so, my country's pauper-speech
Constrains me sadly. As I can, however,
I'll touch some points and pass. In such a wise
Course these primordials 'mongst one another
With intermotions that no one can be
From other sundered, nor its agency