The renal dysfunction in the chronic compensated pyelonephritis means a selective decrease of the maximum osmotic concentration power, the ammonia secretion and the total secretion of hydrogen ions in the glomerular filtration rate, proximal reabsorption of the fluid of the tubule, excretion of osmotically free water and acidity of the urine which can be titrated. 2. The functional distrubances observed in chronic pyelonephritis do not as a whole differ from those disturbances in chronic compensated glomerulonephritis, but in the disease first mentioned there is in every case no decrease of the endogenic creatinine clearance and the maximum water diuresis. 3. The latent chronic pyelonephritis differs from the latent chronic glomerulonephritis by a normal endogenic creatinine clearance and maximum water diuresis and by a decrease of the ammonia and hydrogen ion secretion. These disturbances to a certain extent may be regarded as specific for the chronic pyelonephritis. In comparison with the chronic hypertonic pyelonephritis in the chronic hypertonic pyelonephritis the maximum water diuresis is normal and the titratable acidity is slightly increased. 4. The kind of renal dysfunctions can be of importance for the differential diagnosis between chronic glomerulonephritis and chronic pyelonephritis particularly in the latent forms of the two diseases.
