Dr. Apert is attending physician to the Hôpital des Enfants malades. He has published several other works on pediatrics and pathology. This book is written for the practicing physician rather than for the immunologist, and is especially valuable to the pediatrician. In discussing immunity, the terminology of Bordet and the French school is used. The first chapters contain much of historical interest, and the following chapters give a concise account of the diseases in which vaccines and serums are used in prevention or cure. The value of the work is enhanced by the incorporation into it of the results obtained in the Hôpital des Enfants malades and in the armies of the Great War. In addition to the description of the uses of vaccines and serums, the chapter on intestinal infections contains an account of the recent work on bacteriophages.