Apollo's Laboratory - continued...

The Athletic Experimenter

At the time the copper engravings for the second volume of Thierische Elektricität were produced, Du Bois-Reymond was teaching anatomy at the Prussian Academy of Arts. Like the anatomical drawings of art students, Du Bois-Reymond's representation of a youthful experimenter was based on a model of a particular kind. Du Bois-Reymond's brother, David-Paul Gustave, posed for the photograph on which the illustration of the young experimenter was based.

This self-experiment that Du Bois-Reymond conducted with dozens of subjects in his laboratory aimed to show that the subject's voluntarily contracted arm muscles created electrical current on his body surface strong enough to deflect the magnetic needle of a galvanometer. The current generated during the muscular contraction was conducted via the subject's index finger, which was immersed in a chamber of salt solution electrically connected to the galvanometer by a metal electrode and copper wire. To promote the conduction of current, the subject's upper body was unclothed. To create a perceptible deflection of the galvanometer's magnetic needle, the subject had to have especially good control of his body. Du Bois-Reymond described the decisive moment in a letter to Alexander von Humboldt:

Just at this instant, I tighten all the muscles of my arm so that I produce an equilibrium between the flexors and extensors of all the joints in the limb, somewhat as one does in gymnastics schools, gingerly testing one's muscular development. ... All other things being equal, the size of the deviation depends largely on the level of development and exercise of the muscles. I have pretty strong arms; until now, of all the many scholars who have undergone this experiment in my laboratory, I have found none with whom it has succeeded better than with myself. There are also people who cannot produce a perceptible deviation of my galvanometer needle, but in these cases, I am not convinced that the muscles achieve the necessary degree of contraction.

Of course, the figure of Apollo was on hand to help represent the nudity and athleticism necessary for this self-experiment. In classical mythology, Apollo was not just an excellent archer but a talented gymnast (gymnos means "nude") heralded as the first winner of the Olympic games.