Balzac's serous apoplexies. The hesitant acceptance of the discovery of the cerebrospinal fluid by Magendie.

The diagnosis of a "serous apoplexy," customary in the first half of the 19th century, was based on the lack of knowledge regarding the normal presence of the cerebrospinal fluid. Balzac's descriptions of three cases of serous apoplexy draw our attention to the fact that the discovery of the cerebrospinal fluid by François Magendie was not assimilated into clinical medicine until the second half of the 19th century.