Professor of Physiology in the University of Geneva. FIFTEEN years ago, when repeating the experiments of Hitzig and Fritsch on the excitable area of the cerebral cortex, I found some new properties of this cortex, and gave a new explanation of the well-known results of its electric excitation. These facts, previously announced in the 'Giornale Imparziale Medico' of Florence, were described first in the appendix to the second edition of my ' Lezioni di Fisiologia Sperimentale,'