An Introduction to Theoretical and Applied Colloid Chemistry: The World of Neglected Dimensions. By Dr. Wolfgang Ostwald, Privatdozent in the University of Leipsic. Authorised translation from the German by Dr. M. H. Fischer, Eichberg Professor of Physiology in the University of Cincinnati. (New York: John Wiley and Sons, Inc. London: Chapman and Hall, Ltd. 1917.) Price: 11s. 6d. net.