Engines of Our Ingenuity

No. 703:
LEONARDO AND EMBRYOS

by John H. Lienhard

Click here for audio of Episode 703.

Today, an odd parable of birth and human vision. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Here's a drawing by Leonardo da Vinci -- that clear-eyed observer of the world and everything in it. It's one of several cutaway views of a man and woman engaged in sexual intercourse. He hasn't got their interior anatomy right -- not yet. He didn't start dissecting people and animals until later.

The drawing has a chilling detachment -- almost a bathroom wall detachment. But Leonardo is seldom finished when we think he is. His inscrutable Mona Lisa vision reminds us how multilayered the world is, beneath its appearances.

Leonardo worked very hard to let nature speak through his brush without subjective interference. And he'd just started to wrestle with the most basic human function -- with procreation.

A few years later, he made a painting that hasn't survived. But his study sketches do. We also have descriptions and versions by other artists. It shows Leda and the Swan. Leda, of course, mated with Zeus, who came to her in the form of a swan.

Leonardo's Leda is a naked and sensual Earth Mother. At her feet, plump laughing children emerge from broken swans' eggs. All around, plants, ripe and rich, burst with reproductive power.

Art historian Kenneth Clark believes that one of those cold studies of intercourse was a preliminary sketch for the Leda masterwork. Leonardo the scientist had struggled with the mystery of human reproduction at a deeper level than was obvious.

And he wasn't done yet. In 1512, now 60, Leonardo devoted a whole notebook to embryology. In it he produced the first drawings of a baby in the womb. He dissected oxen and he dissected at least one dead mother with her unborn child.

He takes on complex anatomical questions. How does the child feed and void? What tissues tie the child and the mother? He didn't get everything right. But he laid ground for people like Fabricius, who worked out the details 80 years later.

So we gaze at that embryo, curled up and small. It is human latency, powerfully contained and powerfully expressed. It is an old man's contemplation of the primacy of human life.

Leonardo's unrelenting belief that truth is revealed in nature brought him at last to the ultimate act of human creativity. In an odd way, that tiny human form, curled up in a ball, about to flower into the world, might be one of the most powerful images Leonardo left for us.

And, seeing that child, we know that Leonardo's search for external truth has led, at last, to a far more internal truth. We know that he's reached a truth not only deep within the human body -- but deep within his own psyche as well.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Clark, K., Leonardo Da Vinci (revised edition). New York: Penguin Books, 1988.

Clayton, M., Leonardo Da Vinci: The Anatomy of Man. Boston: Bulfinch Press, 1992. (This is the catalog of an exhibit at the Museum of Fine Arts, Houston. The exhibit ran from June 28, 1992 to February 21, 1993.)

O'Malley, C.D., and Saunders, J.B. de C.M., Leonardo da Vinci on the Human Body. New York: Henry Schuman, 1953.

Adelmann, H.B., The Embryological Treatises of Hieronymus Fabricius of Aquapendente, Vols. 1 and 2. Ithaca, NY: Cornell University Press, 1942 (including a facsimile of the 1621 version.)

Belt, E., Leonardo the Anatomist. New York: Greenwood Press, 1969. (Original printing, University of Kansas Press, 1955.)

I am grateful to Ken Soh at the Museum of Fine Arts, Houston, for his counsel on this episode.

For more on Leonardo and Leda, see Episode 1183.


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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