Gustave Dax and his fight for recognition: an overlooked chapter in the early history of cerebral dominance

The year 1865 was revolutionary in neuroscience. In this year, three papers were published on the topic of cerebral dominance for speech. These papers were authored by Paul Broca, Marc Dax, and Gustave Dax, and they contributed to a priority debate that cannot be easily resolved. Gustave Dax claimed that his long dead father had written a memoir and presented it orally in Montpellier in 1836, thus making him the first person to write about cerebral dominance. He also claimed that he was the second person to write on the subject, the first to support his father's claims, and the first to try to localize the center for speech in just one part the left hemisphere, the middle (temporal) lobe. Paul Broca, however, was now getting much of the credit for these discoveries. To set the record straight, Gustave published several letters. This paper presents translations of Gustave's letters of 1866, 1875, and 1877, as well as the historical note written by Raymond Caizergues in 1879, and recreates the events that triggered the younger Dax's anger.