At some point at the very close of the eighteenth century, Alexander von Humboldt stuck a silver rod up his anus and a zinc disc in his mouth and basically electrocuted himself. It was quite an experience, so his 1797 treatise, Versuche über die gereizte Muskel- und Nervenfaser nebst Vermuthungen über den chemischen Process des Lebens in der Thier- und Pflanzenwelt, tells us; the shock on his body produced strong convulsions and sensations that included ‘pain in the abdomen, increasing activity of the stomach and alteration of the excrement’. Humboldt's idea was to include his entire body in a galvanic chain so that he could experience himself as the object of one of his experiments. Such experiments, which included the galvanisation of his eyes, teeth and tongue, were designed to investigate Lebenskraft in terms of what Humboldt called a vital chemistry in which the stimulus of excitable matter produced ‘chemical alterations and combination’ (chemische Mischungsveränderung).

For the early Romantics, chemical activity signified the productive power behind an organic structure. It was life, the very movement of spirit in the sense of a creative, poetic force that unites the parts to the whole; as such it was the physiology of thought itself. But the Romantic circle in Jena, which included Humboldt, knew that this Lebenskraft was an elusive force that always evaded analysis.