This gives a good critical survey of the colloidal behavior of elements and their inorganic compounds, with particular reference to their rôle in the development of colloid science. It is concerned primarily with the methods of formation, properties and application of the elements in the colloid state, which includes their uses or their tentative uses in medicine. The elements included are gold, silver, copper, mercury, alkalis and alkaline earths, lead and miscellaneous colloidal metals including antimony, the iron and platinum families and the nonmetallic elements carbon, sulphur, selenium, tellurium and iodine. The essentials of this part of colloid chemistry are presented in a clear, concise, accurate style, with numerous references to the literature. The therapeutic discussions, however, give one the impression of a chemist, with the will to believe, peeking at medicine through the keyhole. The facts are that most of the reported benefits of colloidal therapy do not withstand