IN STUDYING the composition of urine in infants under 3 months of age, König and Lederer1 observed that the capacity of young infants for concentration is low. The same conclusion was drawn from the experiments of McCance and Young.2 Further confirmation of this was made by Heller,3 who also succeeded in demonstrating that the kidneys of newborn infants do not react to the antidiuretic hormone of the posterior lobe of the pituitary.
In a later study McCance4 stated that the low osmotic pressure of urine in newborn infants is increased only in the case of a considerable shift in the concentration of the nonprotein substance of blood plasma. From this observation the conclusion was drawn that in the early period of life the concentration of urine depends soley on the glomerular filtrate, since there is unsatisfactory tubular function at that age. This was proved by the