Whoever keeps himself informed of the course of modern scientific investigations is likely to be aware that during the last decade especial attention has been given at the Salpêtrière to that strange physical or psychical force known as hypnotism. M. Charcot, chief of the school of the Salpêtrière, has particularly distinguished himself by his researches. Attacked at first by his professional brethren, it has been his good fortune to live to see the scientific value of hypnotism acknowledged, and to be triumphantly readmitted to the Academy of Sciences, which had at first stigmatized his investigations as mere charlatanism. Charles Féré, an assistant physician at the Salpêtrière, with Richer, Bourneville, and nearly a score other distinguished men, have pursued their investigations with great zeal and thoroughness, and have produced a valuable literature devoted to this intricate subject. It will be easily understood that all the physicians at the Salpêtrière, and especially the younger men, could not fail to be deeply interested in this new and fascinating branch of science. The facts upon which had been founded the theories of mesmerism, animal magnetism, and other shadowy systems were reduced to order and scientifically tested. M. Charcot and his associates worked with much care and thoroughness, and, without being able to solve the mystery of the force with which they dealt, they proved its value as a therapeutic agent. In the cure of nervous diseases, and in dealing with hysterical patients, they obtained remarkable and satisfactory results. They were even able to alleviate suffering by simply assuring the patient, while in a hypnotic sleep, that he would be free from pain on waking. To the outside observer no feature of this strange power is more remarkable than the influence the hypnotist may exert over his subject after the trance is broken. A hypnotized person may be told to perform any act on awaking, and, when seemingly restored to his normal condition, bears the impress of that command so strongly that he is urged to obey it by an irresistible impulse. It is quite as easy, moreover, to foist upon the patients the most extraordinary delusions. The subject is told that upon awaking a bottle will seem to be a lamp, a blank card a picture, or any other deception which comes into the mind of the hypnotist; and so perfect is the working of this mysterious and terrible law that the delusion is accomplished to its minutest details.