The vital capacity of the lungs is the volume of air which can be expelled after the deepest possible inhalation. We have been unable to find any recorded measurements of vital capacity in normal children, and this was one reason for making these determinations. West 2 has shown that vital capacity in adults varies with the surface area more closely than with any other standard tried. It was not our object to determine the truth of this relation in normal children, but it came out in our work. Peabody 1 has demonstrated the importance of the reduction in vital capacity as an index of the tendency to dyspnea in cardiac disease and has emphasized the importance of vital capacity determinations in diagnosis, prognosis and treatment of vital capacity. It is our primary object to confirm, with regard to children, Peabody's observations in adults, but naturally the vital capacity of normal