The contributions of Dr. Mierzejewski, Professor in the Medico-Chirurgical Academy of St. Petersburg, to our knowledge of the structure and pathology of the nervous system have earned for him a high reputation. His observations on the histology of the brains of idiots are of much scientific value, and as the field is wide and in a great degree unexplored, it is to be hoped that he will steadily prosecute his researches. The distinguished Professor has gathered round him a group of medical men devoted to the study of neurology who not only record the results of their observations on the cases presented by the asylums and hospitals of St. Petersburg, but also prosecute original researches in his laboratory with a view to filling up any “leak” which presents itself in our acquired knowledge of the physiology and pathology of the nervous system. Instead of taking up further time with praise, however well deserved, it will be better for our readers if we recapitulate some of the results arrived at by this ardent and industrious band of observers. With the exception of Dr. Mierzejewski's own memoir, all these contributions, or at least all these in our hands, have been published in the “St. Petersburger Medicinische Wochenschrift.”