This edition is in some respects a new work. The section on nervous diseases has been revised and new chapters added. The articles on poliomyelitis and pellagra are rewritten so as to embody recent researches. The author gives a good review of the theories of hysteria. While describing the views of Freud, he follows in general the outline presented by Charcot and his school. On the other hand, in the section on insanity Peterson describes in some detail the method of psychanalysis as used by Freud. The section on insanity has been rearranged and rewritten to correspond to the more modern method of classification. The work has become a standard text-book on the subject of which it treats, and the revision bids fair to enable it to maintain the high position that it has attained.