The first detailed study and illustration of Ammon’s horn sclerosis in epilepsy and the men behind it: Emil Bratz (1868–1934) and Otto Hebold (1856–1945)

Abstract Ammon’s horn sclerosis (AHS) is a frequent, important, and intriguing central nervous lesion in human epilepsy. As early as 200 years ago in 1825, AHS was recognized and described macroscopically first, but its significance was debated. After an initial microscopic report from postmortem brain tissue in 1880 made by Wilhelm Sommer, it was Emil Bratz (1868–1934) who published the first systematic investigation of AHS in epilepsy in Europe, performed under the directorship of Otto Hebold (1856–1945) at Wuhlgarten, an early German institution built for the care of patients with epilepsy in Berlin. In 1899, a paper published by Bratz contained a precise illustration of AHS tissue characteristics: a beautiful woodcarving. The picture as well as Bratz’s writings encompasses all the hallmarks of AHS. Here, we revisit this milestone paper of epilepsy pathology in a historical context including several aspects so far unknown or not readily available. Bratz, supported by Hebold, recognized the pathognomonic histological pattern of AHS, as seen in certain cases of epilepsy, at a time when epilepsy and its anatomical correlates were still poorly understood. As shown here, this contribution was widely recognized at the time, represented a seed point for many researchers to come, remains cited to this day, and is worth being remembered along with the two men behind it.