Johannes Peter Müller - continued...

To improve communication among German-speaking physiologists, Müller founded the Archiv für Anatomie, Physiologie und wissenschaftliche Medicin in 1834. His journal contained yearly reports on physiological and anatomical research throughout Europe and quickly became one of the most respected scientific periodicals. From 1834 onward, however, Müller’s own research focused increasingly on observations of animal structures and less and less on their physiological functions. In 1838, he applied his student Theodor Schwann’s (1810-82) cell theory to pathological studies, demonstrating in his work Ueber den feineren Bau der krankhaften Geschwülste (On the Fine Structure of Pathological Tumors, 1838) that tumors were made of cells. In one of his final physiological investigations, Ueber die Compensation der physischen Kräfte am menschlichen Stimmorgan (On the Compensation of Physical Forces in the Human Voicebox, 1839), he used a severed head and his wife’s piano to study the way that the human voice produces particular tones.

The project that consumed most of Müller’s energy and attention was the classification of marine organisms. In the late 1830s, he developed a new classificatory system for the myxinoids (hagfishes) and plagiostomes (cartilaginous fishes such as sharks). In the 1840s, he continued this work with studies of the cyclostomes (lampreys) and ganoid (scaly) fishes. Müller was particularly intrigued by echinoderms, animals with radial symmetry such as sea-urchins and starfish. On his research trips, he used a net he had specially designed to scoop floating echinoderm embryos from the sea surface, a technique that he called “pelagic fishery” (Rheinberger 1998). Müller focused on organisms that fell along the borders of previous classificatory systems, attracted by the challenge they presented. He suffered a serious depressive episode in 1852 when he discovered what appeared to be slugs developing in the gut cavities of sea-cucumbers, since the classificatory system he had been developing could not account for the appearance of one organism inside of another.