827

Comparative study of the organs of sense in men and animals.

I have found that in the composition of the human body as compared with the bodies of animals the organs of sense are duller and coarser. Thus it is composed of less ingenious instruments, and of spaces less capacious for receiving the faculties of sense. I have seen in the Lion tribe that the sense of smell is connected with part of the substance of the brain which comes down the nostrils, which form a spacious receptacle for the sense of smell, which enters by a great number of cartilaginous vesicles with several passages leading up to where the brain, as before said, comes down.

The eyes in the Lion tribe have a large part of the head for their sockets and the optic nerves communicate at once with the brain; but the contrary is to be seen in man, for the sockets of the eyes are but a small part of the head, and the optic nerves are very fine and long and weak, and by the weakness of their action we see by day but badly at night, while these animals can see as well at night as by day. The proof that they can see is that they prowl for prey at night and sleep by day, as nocturnal birds do also.

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

Notebooks of Leonoardo da Vinci
XIV: Anatomy, Zoology and Physiology.
. . .
807,
808
On corpulency and leanness.
809,
810,
811
The divisions of the head.
812,
813
Physiological problems.
814,
815
The divisions of the animal kingdom.
816,
817
Miscellaneous notes on the study of Zoology.
818,
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
. . .