Da Vinci's Ghost (22 page)

How much of this Leonardo was able to absorb directly by reading is impossible to say. The books and manuscripts he bought for himself and encountered in libraries were indeed shot through with the human analogy. Most were written in archaic, medieval, and specialized varieties of Latin that would have been difficult for him to understand in full.

But many would still have provided him with a cursory but memorable introduction to ideas about the microcosm, in their illustrations.

L
EONARDO WAS A
visual thinker, first and foremost. So as he struggled to make sense of what he read, he did what anybody groping through a difficult work does: he turned to the pictures for help. And as he flipped from image to image, what came to life before his eyes must have been an almost cinematic
montage: phantasmal visions of the human body spread-eagled on the page again and again, deployed there as an organizing principle for knowledge. He saw schematic diagrams in which the body incorporated the elements and unified the cosmos. He saw mystical drawings in which it symbolized the human and the divine. He saw maps in which it became one with the world. And, in abundance, he saw medical and astrological illustrations in which the human body, laid bare, revealed the secret inner workings of the microcosm.

This last category of images is likely to have interested Leonardo most of all. There was certainly no shortage of them. Early versions of such figures as Bone Man, Nerve Man, and Muscle Man appeared in twelfth- and thirteenth-century texts. By the fifteenth century these figures not only had proliferated, appearing in stock form in all sorts of medical miscellanies, but had also spawned a variety of (predominantly male) progeny, among them Zodiac Man, in whom the various celestial signs and bodies were linked, with increasing anatomical specificity, to parts of the body (
Figure 36
); Bloodletting Man, an astromedical relative of Zodiac Man, whose body indicated to barber-surgeons and physicians where, and when, to bleed patients (
Figure 37
); and the long-suffering Wound Man—a glorious, if inadvertent, symbol of the human condition, whose pierced, bludgeoned, and maimed body was designed to itemize for doctors the various injuries they might encounter in their rounds (
Figure 38
).

Leonardo combed through medical texts to learn whatever practical information he could about the human body. But since he could never help thinking by analogy, he soon found his way to the idea—discussed by the ancients and popularized by medieval Arab writers—of the body as a miniature anatomical
model of the world. In about 1490 he summed up his thoughts on the subject.

Figures 36, 37, and 38. Top left:
Zodiac Man (c. 1410), showing the relationship between the body and the signs of the zodiac.
Top right:
Bloodletting Man (c. 1410), showing where and when patients should be bled for various ailments.
Right:
Wound Man (c. 1450), showing the kinds of injuries a medieval doctor would be likely to encounter.

By the ancients
man was termed a lesser world, and certainly the use of this name is well bestowed, because his body is an analogue for the world, in that it is composed of water, earth, and fire. Just as man has in himself bones, the supports and armature of the flesh, the world has rocks; just as man has within himself a lake of blood, in which the lungs increase and decrease in breathing, so the body of the earth has its oceanic seas, which likewise increase and decrease every six hours with the breathing of the world; just as in that lake of blood the veins originate, which make ramifications throughout the human body, similarly the oceanic sea fills the body of the earth with infinite veins of water. Nerves are lacking in the body of the earth. The nerves are not to be seen there because the nerves are made for the purpose of movement, and the world being perpetually stable, movement does not occur.

Not surprisingly, Leonardo grew frustrated in his anatomical studies by the texts he was able to find—works full of obvious untruths and subtle misperceptions, which he would later describe as “
tortuously ponderous, long-winded, and confused
.” And those ghastly illustrations! The kind of anatomical text he could really learn from—a comprehensive guide to the human body, based on empirical investigation but illustrated by a master artist—seemed simply not to exist. If he wanted such a treatise, he realized, he had only one option. He would have to produce it himself.

L
EONARDO LAID OUT
his initial idea for an anatomical treatise in early 1489. It would be titled
On the Human Body
, he wrote in his notes, and it would be unlike anything ever seen before. Under the heading “On the Order of the Book,” he laid out his plans in ambitious detail:

This work should begin
with the conception of man, and describe the form of the womb, and how the child lives in it, and to what stage it resides in it, and in what way it is given life and food. Also its growth, and what interval there is between one degree of growth and another, and what it is that pushes it out of the body of the mother, and for what reason it sometimes comes out of the mother’s belly before due time. Then you will describe which parts grow more than others after the infant is born, and give the measurements of a child of one year. Then describe the grownup man and woman, and their measurements, and the nature of their constitution, color, and physiognomy. Then describe how they are composed of veins, nerves, muscles, and bones. This you will do at the end of the book. Then, in four drawings, represent the universal conditions of man: that is, joy, with different ways of laughing, and draw the causes of laughter; sorrow, in different ways, with its cause; strife, with different acts of slaughter, flight, fear, ferocity, daring, murder, and all things which pertain to such cases. Then draw work, with pulling, pushing, carrying, stopping, supporting, and similar things. Then describe attitudes and movement. Then perspective, through the function of the eye; and on hearing—you will speak of music. And treat of the other senses. Then describe the nature of the senses.

Leonardo being Leonardo, this was only the beginning. As the idea for the book took hold, he began jotting down
other topics that he would have to cover
: how the eyebrows were raised and lowered; how the eyes opened and closed; how the mouth and lips moved to form different facial expressions; how nerves transferred movement from shoulder to elbow to hand to fingers, and from thigh to knee to foot to toes. Soon the ideas were tumbling out in a free-associative cascade:
“Represent whence catarrh
[phlegm] is derived. Tears. Sneezing. Yawning. Trembling. The falling sickness. Madness. Sleep. Hunger. Sensuality. Anger, where it acts in the body. Fear, likewise. Fever. Write what the soul is. … Illustrate whence comes the sperm. Whence the urine. Whence the milk. How the nourishment proceeds to distribute itself through the veins. Whence comes intoxication. Whence the vomit. … Whence dreams.”

This was a far cry from the plodding
Anatomy
of Mundinus. But Leonardo planned to distinguish his treatise from all others not just in the audacity of its scope. Having come to appreciate in his engineering and architectural studies just how efficient and powerful a tool a well-drawn image could be, he made a momentous decision: his treatise would be primarily visual, not verbal. He would undertake an exhaustive hands-on investigation of the human anatomy and then would present the results of that investigation with unprecedented graphic precision, using a range of new architectural and perspectival drawing techniques never before applied to anatomy: plans and elevations, cutaway views, see-through body parts, rotating images, and more. What he was beginning to envisage was nothing less than a comprehensive anatomy of the microcosm:
a three-dimensional map of body and soul. He said as much himself in about 1509 in another note spelling out plans for
On the Human Body
—a work that, regrettably but not surprisingly, he would never manage to finish.

“You will have set before you
the cosmography of the lesser world,” he wrote, “on the same plan as was adopted before me by Ptolemy, in his
Geography.
… And, thus, might it so please our Creator that I may be able to demonstrate the nature of man.”

W
RITE WHAT THE SOUL IS
.

Leonardo very deliberately included that remark in the list of anatomical features and functions he wanted to cover in
On the Human Body
. That’s because, at least at this stage in his career, he believed the soul to be a physiological entity.

Here Leonardo was getting himself involved in a debate that had kept philosophers busy since ancient times. There were two basic positions. Either the soul had an independent existence, as Plato had proposed, and served only temporarily as an adjunct to the body, during a person’s life; or it had no independent existence, as Aristotle had proposed, and formed an inseparable part of the body, one that quickened and died with it, just like any other organ.

Leonardo, whose notes show him to have read up on this subject, took Aristotle’s side. Moreover, he believed, as many early philosophers had done, that the soul did not inhabit the body as a whole but instead had as its seat the noblest, most elevated part: the head. Leonardo’s study of the frog seemed to confirm this idea. But by 1489 he had realized that the study
of animals would never provide him with the detailed information he needed to produce a truly comprehensive map of the human anatomy. Nor would studying traditional medical texts or attending the occasional public dissection. His only option was to start taking apart the human body himself.

For an investigator as insatiably curious as Leonardo, whose interests had for years been shifting from surface appearances to interior causes, this was an inevitable decision. Once he started thinking about the human body, he simply had to learn as much as he could about it—and that meant going
in
. The decision also makes sense given his interest in the relationship between architecture and anatomy. Already he had wandered around inside the bodies of churches, studying their anatomy, meditating on their health, searching for the design principles that animated them, and pondering the design of their domes. So why not now turn to the thing itself?

Leonardo may also have been nudged toward his human dissection by a surprising source:
The City of God
, by St. Augustine. Any number of the scholars whom Leonardo sought out for help in learning about the nature of the soul might have referred him to the work, written in the fifth century and long considered by Europeans one of
the
indispensable texts in any program of higher education. Medieval manuscripts of the work existed in abundance, and printed editions were widely available: the first edition had been published in 1467, part of the first wave of books to be printed in Europe, and before the end of the fifteenth century
some twenty different editions
had appeared. By the early 1500s, at the latest,
Leonardo himself owned a copy
.