Acknowledgment and thanks for the use of the following selections are herewith tendered to the Open Court Publishing Company, La Salle, Ill., for "Senses of Insects," by Auguste Forel; to G.P. Putnam's Sons, New York, for "Prolongation of Human Life" and "Nature of Man," by Elie Metchnikoff; and to the De La More Press, London, for "Hypnotism, &c.," by Dr. Bramwell.