The Manuscripts of Leonardo da Vinci, Vol. 4

[DATE OF THIS MANUSCRIPT. — DEATH BY OLD AGE. — REINFORCED DIKES].

I. — Begun in Milan on the 12th day of September 1508 original: "Comincato ammilano addi 12 disettembre 1508".
Death in the elderly, when it occurs without fever, is caused by the veins that go from the spleen to the portal of the liver; they thicken so much in their lining that they close up and no longer allow passage to the blood that should nourish them.
The continuous flow of blood through its veins causes these veins to thicken and become callous in such a way that, in the end, they close up and prevent the blood from flowing.
The spaces or hollows of the veins in animals, through the long passage of the fluid humor: in Renaissance medicine, "humors" were the vital fluids of the body that nourishes them, become callous and eventually close. The hollows of the veins of the earth Leonardo frequently compared the "veins" of the earth (water channels) to the veins of the human body., through the long and continuous flow of water, tend instead to widen.
Willow roots do not allow the banks of canals to be destroyed; and the willow branches, nourished within the thickness of the bank and trimmed low every year, grow thicker and create a continuous weave of shoots; and thus you have a bank that is alive and of one piece.

[ Figure: ] c d a b e f

I'. — Begun in Milan on September 12, 1508. This section in the source was a 19th-century French translation of Leonardo's Italian notes above.
Death in the elderly, without fever, is caused by the veins which, going from the spleen to the portal of the liver, thicken so much in their skin that they close, and no longer give passage to the blood which nourishes them.
The continual course of blood in its veins causes these veins to thicken and become callous, in such a way that at the end they close and prevent the blood from its course.
The spaces or concavities of the veins of animals, with the long course of the humor that nourishes them, become callous and in the end narrow. The concavities of the veins of the earth, by the long and continuous course of water, go on widening. Willow roots do not let the dikes of canals be spoiled; willow branches nourished through the thickness of the dikes, then cut low, thicken each year, and are made of [augmented by] continual shoots; and thus you have a living dike of one piece.

1. Leonardo da Vinci’s autograph pagination.
2. The writings of Leonardo da Vinci, by Charles Ravaisson-Mollien.
3 and 4. Text also cited by scholar Jean Paul Richter.
5. Under the ink of the first line, a draft in red chalk can be read: "September 12, 1508." Likewise under the following lines: "the veins... elderly... callous by continuous motion... blood... moves." Also in red chalk: the figure above these lines.

[LIGHT AND SHADOW].

[Figure:] c a o b e d f
— The surface of every opaque body participates in the color of its object —
THAT PART OF THE SURFACE OF OPAQUE BODIES WILL PARTICIPATE MOST IN THE COLOR OF ITS OBJECT WHICH IS NEAREST TO IT.
Let a b [ a o b ] be the opaque body, and c d the luminous object, and e f the shadowy object; I say that the middle of this opaque body, o, will participate equally in both objects, and the part a o will be more luminous than the part o b; it will be more illuminated the closer it is to the light, and likewise the part of this body that is darker, being closer to the shadowy object, will be more shaded.

[Figure:] c a o b e d f
The surface of every opaque body participates in the color of its object.
THAT PART OF THE SURFACE OF OPAQUE BODIES PARTICIPATES MORE IN THE COLOR OF ITS OBJECT WHICH IS CLOSER TO IT:
Let a b [ a o b ] be the opaque body, and c d the luminous object, and e f the shadowy object; I say that the middle of the opaque body, o, participates equally in one and the other object, and that the part a o is more illuminated than the part o b; it will be more illuminated the more it is near the luminous one, and likewise the part of the body that is more obscure which is near the shadowy one will be more shaded.