June 3, 2012

The image on page 401 of George W. Hunter’s 1907 Elements of Biology is strikingly out of place. It is a Greek bronze flattened to a black silhouette. A woodblock engraving in a textbook otherwise illustrated with halftone photographs. A relic of Renaissance anatomy covered by the soot of the Age of Steam. Yet there it stands, owning the page.

The Nervous Icon (as I’ve come to call the image) was a popular feature in biology textbooks into the 1950s. Picked up, rephotographed and copied with apparently little concern for image quality, artistry, copyright or context. It was treated poorly, just plopped in and barely referenced in the later texts in which it appeared.

But something told me there was a story here. I felt as if the Nervous Icon was a courier carrying a secret message from the past.

It turns out that tracing the history of this image – exploring when it was first cut, how it was reproduced, where it appeared, and why it remained popular even as similar classically styled illustrations were retired – reveals surprising connections between the seemingly disparate topics of printing technology, print piracy, electricity, telegraphy, spirituality, abolition, and that most central of nineteenth century anxieties, masturbation. The Nervous Icon’s secret is that, in its hyper-nakedness, it warned of the dangerous interconnectedness of the body, where stimulation, or over-stimulation, of any one part would cause damage to the entire system.

I have identified nearly 100 instances of the Nervous Icon from books older than Hunter’s Elements. I’ve written before that the anonymous carver of the Nervous Icon most certainly used as reference illustrations published in Andreas Vesalius’ famous 1543 Renaissance anatomy, De Humani Corporis Fabrica. But strangely, while similarly posed and frequently associated images of the human skeletal system, muscular system and circulatory system could be traced back through nearly identical copies rendered in the eighteenth century, seventeenth century or earilier, the Nervous Icon, as far as I have been able to determine, dates only to the early 1840s, with the eariest example so far found appearing in William Benjamin Carpenter’s Popular Cyclopaedia of Natural Science, published in London in 1843.

The earliest domestic (U.S.) example I’ve found appears in Calvin Cutter’s Anatomy and Physiology, published in Boston in 1847.[1] The identical illustration appears in Cutter’s 1850 Anatomy, Physiology, and Hygiene. A nearly identical version appears in Thomas Lambert’s Human Anatomy, Physiology and Hygiene, published in Hartford in 1854. And an identical example can be found in Dionysius Lardner’s The Museum of Science and Art Vol. VIII, a popular British encyclopedia published in London in 1855.

Over the next century, reprints, copies and re-drawn variations sprouted up everywhere.

It is not strange that an image like the Nervous Icon got around in the mid-nineteenth century. According to Sarah Crider Arndt (see comment in Sarah’s blog, Print on the Periphery), publishers often copied illustrations by hiring local engravers to cut new plates. Slow communication between commercial centers in the United States, non-existent international copyright laws, the imperative for accuracy in scientific illustration and the difficulty of creating original works when cadavers are your models made pirating both possible and profitable. Despite cooperative trade agreements, which gradually brought control to whole-text plagiarism, pirated illustrations, particularly anatomical illustrations for which the term “original” had little meaning, were copied and copied again, following conventions that were centuries old.

From the Renaissance on, illustrators of human anatomy had referenced classical Greek statuary to create the silhouettes within which they would display the body’s inner workings. Through its many piratical admirers, Andreas Vesalius’s anatomy gave birth to a small number of standard illustration armatures. These figures, always male, obviously white, were frequently rendered with their weight asymmetrically distributed, in motion, with one hand open and the other with its forefinger delicately extended.

The Nervous Icon was clearly built with parts first rendered in Vesalius, and it carries a strong family resemblance to other statuesque frames then in common circulation. However, the image is unusual for a number of reasons. First, while the human lymphatic, circulatory, skeletal and muscular systems had long been rendered within a human silhouette, the human nervous system was most often rendered as sort of an anthropomorphized bush. Second, its outline appears nowhere in the many popular European anatomical dictionaries and encyclopedic works available. Third, the reversal, white lines on a black body, is somewhat unusual. Finally, and perhaps most curiously, the Nervous Icon seems to have materialized on two sides of an ocean simultaneously, without the telltale signs of it being re-engraved by a lesser hand when it traveled west.

To understand how this was possible, and why it is important, we need to detour briefly into a short history of printing in the industrial era.

By the 1840s, three methods had been developed to imprint images on paper: intaglio, which typically involved an engraved copper or steel plate; planographic, which involved a lithographic stone; and relief, which usually relied on a small but easy to work piece of basswood. All had their advantages and limitations. The key problem with metal and stone was their relative cost, a major hiccup at a time when cheap paper and fast presses were set to feed a large literate population ravenous for stuff to read. But it wasn’t just the materials and skills necessary for metal engraving and lithography that made these techniques expensive. To put text next to image, separate time consuming and waste producing press passes were required.

Woodblock illustrations were far more convenient. They were less costly to cut and, as a relief technology like movable type, could be locked up in attractive page compositions that could be printed in one pass.

But there was a big downside. While woodblocks in the hands of a skilled artist could be carved with a level of detail nearly indistinguishable from a copper plate engraving, that detail didn’t hold up on press. A noticeable decay in quality was apparent after just a few hundred impressions.

The workaround, invented in the early 1700s and in common use by the 1820s, was to make a plate copy by pouring hot metal into a paper mâché mold cast from a locked-up printer’s forme. The result was called a stereotype. Stereotypes were expensive but robust, and once created, could be bent around the drum of a high-speed press and be at the ready if a text proved popular enough to demand a reprint (related story and video). Also, a stereotype, or multiple stereotypes created from a common mold, could be shipped to cooperative printers in other cities to expand the market and beat the pirates. But while good enough for text, because of the material used to make the molds and the pressures required for decent reproduction, stereotypes did not reproduce the details in illustrations very well and tended to damage the woodblock originals.

Which brings us back to the Nervous Icon.

Calvin Cutter’s 1847 edition of Anatomy and Physiology proudly proclaims itself a “third stereotype edition.” However, even with what appears to be a weak printing (further degraded by the low resolution Google scan) the detailed structure of the brain and the sharp points of the finely tapered nerves are well rendered. If the image was printed from a stereotype, and it likely was, the relief image used in the printer’s forme must have been of reasonably high quality. But it almost certainly wasn’t the original woodblock, unless that woodblock was traded between competitors Cutter and Lambert, and managed to travel east across the Atlantic to also end up in Lardner’s encyclopedia.

Here’s where things get a little spooky. It is possible, probable even, that the technique that allowed detailed and near-exact copies of the Nervous Icon to appear in Cutter, Lambert and Lardner’s books is intimately connected to the questions of why the image was imagined in the first place, how it spread and why it proved so popular.

That connection is electricity.

In the late 1830s and into the 1840s electricity was everywhere. It was in the air in the form of “animal magnetism.” It was in the wires in the form of Samuel Morse’s dots and dashes. And it was in our bodies, transmitted through the nerves that most physiologists now agreed were the messengers of sensation. Mesmerists and phrenologists, technologists and scientists, physicians and missionaries were all enthralled by electricity’s almost spiritual properties. As Michael Sappol writes in A Traffic of Dead Bodies, electromagnetism became identified with “the élan vital, the force that animated the living body, and possibly the inorganic universe as well” (153).

From Medical Adviser and Marriage Guide by Martin Larmont (1861).

But sensations magically transmitted at the speed of light caused as much fear as fascination. Many physiologists in the early nineteenth century believed that stimulation, specifically over-stimulation, was the cause of disease. Through what was seen as a more than metaphorical similarity between the nervous system and the telegraphic system, electricity connected concerns about the individual and national body. As Sam Halliday suggests in Science and Technology in the Age of Hawthorne, Mellville, Twain, and James (2007), electricity was a common theme that tied together debates concerning the education of women, the abolition of slavery and fear that middle-class teenage boys could masturbate themselves into madness.

Education in anatomy became a popular rage in the United States in the first decades of the nineteenth century, promoted, according to Sappol, as having “an intrinsically ‘civilizing’ effect.” Critics complained that education in anatomy “tends to render the student a Materialist,” however this complaint was trumped by the “democratic” appeal among an increasing prosperous but also increasingly anxious public insecure in its bourgeois identity; a class “only a thin stratum above the anatomy rioters, and maybe not even that” (Sappol 161).

Strangely, this leads us again back to the Nervous Icon. For while in the air, in the wires and in our bodies, thanks to the invention of Smee batteries and the higher tech Daniell cells, by the 1840s electricity was also flowing in the print shop, there to drive a new process for making copies of woodblock illustrations called electrotyping.

Electrotyping, a process for depositing a thin layer of copper against a graphite coated wax mold, was invented in 1838. By 1841 it was in use among magazine and book publishers in Europe and the United States. It was a relatively expensive process, but the plates or plate components it created were both finely detailed and durable.[2]

Electrotyping allowed for the manufacture of multiple copies of an original woodblock illustration (or a complete composed printer’s forme or any three-dimensional surface – see video). It was used hand-in-hand with stereotyping. For example, compositors at regional newspapers were often sent electrotyped copies of ads that they would then place into a page, along with other ads and movable type, and then stereotype the whole page in preparation for printing. Merchants could also send less expensive stereotypes of their ads to newspapers. But stereotypes made from stereotypes, again because of the material used to make the molds, were of noticeably lesser quality.

Without examining the originals, and perhaps even then, it is impossible to know if the Nervous Icons in Girona, Cutter, Lambert and Lardner’s books were created from a common woodblock, or stereotyped copies, or electrotyped copies of an original. One thing that does seem clear. These images were not re-engraved copies. How do we know that? From the presence of the fine straight dotted lines in the Icon’s left shoulder and wrist, its sides and its calves. These lines are the vestiges of pointers that, in a yet to be identified original, connected to a key listing the nervous system’s various elements.

(UPDATE: Probable original now identified.)

Careful comparison of the Cutter and Lardner images betray their common ancestry. Rather than chopping the leader lines at the edge of the silhouette, as Lambert did, Cutter used one black dash external to the figure to connect the white lines to his 16-point key. These single dashes overlay the longer Lardner lines exactly. The Lambert image, though it has no key, also carries vestigial white lines, most of which overlay the Cutter and Lardner examples exactly, though the line that enters the Lambert torso from the left cuts at a slightly different angle than the other two.

Still, we cannot know for sure if these images, even if they were created from a common original (which I believe to be the case), were stereotyped from stereotypes, stereotyped from electrotypes, or even stereotyped from a common woodblock master. But there is one last clue that I think tips the balance toward electrotypes.

After it was used by Lardner, the “original” version of the Nervous Icon, the version with the vestigial leader lines, disappeared from books, replaced by near-exact but line-free duplicates, most of which suffer from reproductive decay (versions 1.1 through 1.4 in the database). The most degraded example can be found in Sanborn Tenney’s Elements of Zoology, published by Charles Scribner’s Sons in 1875. It looks to be a stereotype of a stereotype of a stereotype. Other publishers seemed to maintain access to something closer to an original master, and good reproductions are found in Smith (1885) and Hunter (1907 and 1911). But then something surprising happens.

Sometime during the print run of George W. Hunter’s 1911 biology textbook, Essentials of Biology, a “new” and much more detailed master was substituted for the version used in the book’s first printings; a master that carried those once mysterious white dotted lines. The same master was then used to create the plates for Hunter’s 1914 book, A Civic Biology, a copy of which I am fortunate to own and therefore can examine directly. This image, though a woodcut, is finely engraved. If it was created from a basswood master, that master had to have been remarkably sturdy. More likely, much more likely I think, the 1914 Hunter version of the Nervous Icon was created from an electrotyped master. This is not the only possible explanation, but it is a logical solution.

A Civic Biology was the last Hunter textbook to feature the Nervous Icon. Other authors used the image, but ironically in the era of “advanced” photolithography and offset printing, the image decayed rapidly and noticeably generation to generation, both in form and print quality. By the mid-twentieth century, instruction regarding the consequences of unnecessary stimulation of the body’s electrical system gave way to more direct instruction over the possible consequences of stimulation. By the 1960s, the nervous system was just one transparent overlay, co-equal with the arteries and veins. The system now called out for special attention in the post-Kinsey, post-Playboy, post-Pill era was, of course, the reproductive.

[1] Nearly all of Cutter’s illustrations appear to be re-engraved copies of illustrations published a couple of years earlier in Smith and Horner’s Anatomical Atlas

[2] As with Gutenberg’s invention of movable type, one of the first uses of electrotypes (or ‘electros’ as they were often called) was in a printing of the Bible (see article). The finely rendered illustrations, though impressive, were considered ‘indelicate’ by some.


Halliday, Sam. 2007. Science and Technology in the Age of Hawthorne, Melville, Twain, and James: Thinking and Writing Electricity. New York: Palgrave Macmillan.

Johns, Adrian. 2009. Piracy: The Intellectual Property Wars from Gutenberg to Gates. Chicago: University of Chicago Press.

Sappol, Michael. 2002. A Traffic of Dead Bodies: Anatomy and Embodied Social Identity in Nineteenth-Century America. Princeton: Princeton University Press.

Stengers, Jean and Anne Van Neck. 2001 (translation of original published in 1998). Masturbation: The History of a Great Terror. New York: Palgrave.


  1. I *love* the Nervous icon! I used some of the overlay in some college artwork, and have the gigantic Human Anatomy fold out book permanently on display, a ready reference, in the bath. Delightful blog, thank you for all your work!

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