This aims to bring together "in concise form for the use of clinicians and workers in clinical laboratories" the most important knowledge relative to the clinical significance of variations in the hydrogen ion concentration of the blood. The first chapter introduces and develops the fundamental conceptions of ph, buffer action, acid-base balance, and alkali reserve. The second and third chapters summarize the existing literature relative to the acid-base balance of normal plasma and of the plasma of persons suffering from diabetes, toxemia, shock and tetany. The final chapter contains directions for the determination of the hydrogen ion concentration. The book as a whole is admirably conceived, and the amount of material and bibliography presented make it a valuable reference handbook for workers in this field. It would, perhaps, be more useful had its subject matter been presented in a more critical and extended form.