1924 · String Galvanometer EEG · Work 1011 of 1,871
A low basement laboratory of a psychiatric clinic in Jena on a summer Sunday, ochre-painted brick walls, a small high barred window letting in warm sunlight, on a heavy oak table a compact string galvanometer, a squat plain polished brass housing between two dark iron magnet blocks with a short brass microscope tube, beside it an arc lamp in a black iron hood and a wooden recording camera with a hand crank, glossy dark photographic paper curling from its slot, on a white porcelain dish two finger-long clay tube electrodes on thin silk-wound cables trailing over the table edge, a hand in a rolled white shirt sleeve turning the crank.
Who
Hans Berger (1873–1941) was a psychiatrist and neurologist in Jena and the first to record the electrical currents of the human brain, the electroencephalogram or EEG. Born on 21 May 1873 in Neuses near Coburg, he studied medicine after a serious accident cut short his military service, and spent his whole academic career at the psychiatric clinic in Jena, from 1919 as professor and director, and in 1927–28 also as rector of the university. He was driven by the idea of a "psychic energy" that he wanted to measure; as late as 1939 he was planning experiments on telepathy. In 1929 he published the first human EEG. The method was taken up widely only when the British physiologist Edgar Douglas Adrian confirmed his findings in 1934. Today the EEG is used among other things to diagnose epilepsy and is the most important method for establishing brain death. Under National Socialism Berger was not a party member but a supporting member of the SS. He endorsed the regime's racial hygiene and, as an assessor and expert witness at hereditary health courts, shared responsibility for numerous forced sterilisations, including some he had applied for himself. On 1 June 1941 he took his own life in Jena.
The moment
On Sunday, 6 July 1924, Hans Berger saw for the first time a current that came from a human brain. He mostly did his research on Sundays, when the disturbing electrical appliances in the building were switched off; the work was done in the basement of the psychiatric clinic in Jena. His subject was a 17-year-old boy who had had a piece of his skull removed in an operation. Around the scar Berger placed two clay electrodes four centimetres apart and connected them to a small string galvanometer made by the firm of Edelmann. Only after several days and many changes to the set-up did the thread show a feeble current. The recording was made on narrow strips of photographic paper that then had to be developed in a darkroom, the instrument had a crank. The picture shows Berger from behind at that crank; the cables run over the edge of the table to the boy, who is not in the picture.
The other side
The first day produced only a feeble deflection, and Berger long distrusted his finding: five years passed before his first publication in 1929. Apart from a few patients, his most important test subjects remained his own family. The same doctor who wanted to watch the brain at work helped a decade later to have people sterilised for supposed hereditary diseases, and shortly before his death he gratefully accepted the offer to serve on the hereditary health court again. Jena University Hospital has since dropped the name "Hans-Berger-Klinik", which its neurology department had carried since the 1950s.
What the sources leave open: No photograph of Berger whose public-domain status is documented was found, so he appears from behind. Sources differ on what he saw that day: a feeble current according to a 2023 paper, a rhythm of about 10 Hz already according to the German society for clinical neurophysiology (DGKN). No instrument from 1924 is known for certain to survive; room, table and clothing are typified.