One of the early methods developed by Craske and Park included what they called Biological Hermeneutic Printing. The aim of this methodology was to isolate and recover viable bacteria from the pages and in a manner that would directly record their various locations in relation to the original text.

Molten blood agar was poured into bioassay dishes and allowed to set. Blood agar was specifically chosen so that the growth of more fastidious species would be encouraged due to its protective ability, which can revive damaged bacterial cells and therefore assist the reawakening of bacterial strains from the 1700’s. Using the aseptic technique, the pages of Book Three from the 1735 copy of Ovid’s Metamorphoses were then impressed upon the agar’s surface. After 20 seconds the pages were removed, and the plates incubated at 25 C for at least a week to encourage the growth of both environmental and disease causing bacteria.

Where bacterial cells from the book’s ancient pages were transferred onto the agar, over time, these microscopic cells multiplied into visible communities. These are clones of the original cell which now contain billions of bacterial cells called colonies. In a very simple sense, at the beginning, each bacterial cell is a set of instructions unique to it (encoded by the cell’s DNA), which when expressed though growth give rise to the vast diversity of the bacterial forms that can be seen in the prints.

In order to allow these complex structures to fully develop, they were allowed to develop and form over a period of many months rather than just a few days.

In an unexpected and serendipitous outcome, when the pages of the book were imprinted onto the agar, not only were ancient bacteria transferred, but this process also cast the indentations made in the paper by the original letterpress printing some 300 years ago onto the agar’s surface. The agar was not only able to recover old biological information but also that which was physical too.


Prof. Charlotte Sleigh
Dr Simon Park
Arts & Humanities Research Council (UK)
University of Kent | School of History | Centre for the History of the Sciences
University of Surrey