839

On involuntary muscular action.

HOW THE NERVES SOMETIMES ACT OF THEMSELVES WITHOUT ANY COMMANDS FROM THE OTHER FUNCTIONS OF THE SOUL.

This is most plainly seen; for you will see palsied and shivering persons move, and their trembling limbs, as their head and hands, quake without leave from their soul and their soul with all its power cannot prevent their members from trembling. The same thing happens in falling sickness, or in parts that have been cut off, as in the tails of lizards. The idea or imagination is the helm and guiding-rein of the senses, because the thing conceived of moves the sense. Pre-imagining, is imagining the things that are to be. Post-imagining, is imagining the things that are past.

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

Notebooks of Leonoardo da Vinci
XIV: Anatomy, Zoology and Physiology.
. . .
819,
820,
821
muscles.
822,
823,
824,
825,
826
Comparative study of the organs of sense in men and animals.
827
Advantages in the structure of the eye in certain animals.
828,
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
. . .