849

On the circulation of the blood.

The waters return with constant motion from the lowest depths of the sea to the utmost height of the mountains, not obeying the nature of heavier bodies; and in this they resemble the blood of animated beings which always moves from the sea of the heart and flows towards the top of the head; and here it may burst a vein, as may be seen when a vein bursts in the nose; all the blood rises from below to the level of the burst vein. When the water rushes out from the burst vein in the earth, it obeys the law of other bodies that are heavier than the air since it always seeks low places.

[Footnote: From this passage it is quite plain that Leonardo had not merely a general suspicion of the circulation of the blood but a very clear conception of it. Leonardo’s studies on the muscles of the heart are to be found in the MS. W. An. III. but no information about them has hitherto been made public. The limits of my plan in this work exclude all purely anatomical writings, therefore only a very brief excerpt from this note book can be given here. WILLIAM HARVEY (born 1578 and Professor of Anatomy at Cambridge from 1615) is always considered to have been the discoverer of the circulation of the blood. He studied medicine at Padua in 1598, and in 1628 brought out his memorable and important work: De motu cordis et sanguinis.]

Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.

Notebooks of Leonoardo da Vinci
XIV: Anatomy, Zoology and Physiology.
. . .
829,
830,
831
Remarks on the organs of speech.
832,
833
On the conditions of sight.
834,
835
The seat of the common sense.
836
On the origin of the soul.
837
On the relations of the soul to the organs of sense.
838
On involuntary muscular action.
839
Miscellaneous physiological observations.
840,
841,
842
The laws of nutrition and the support of life.
843,
844,
845,
846,
847
On the circulation of the blood.
848,
849,
850
Some notes on medicine.
851,
852,
853,
854,
855,
856
The earth’s place in the universe.
857,
858
The fundamental laws of the solar system.
859,
860,
861,
862,
863,
864
How to prove that the earth is a planet.
865,
866,
867
The principles of astronomical perspective.
868,
869
. . .