When Cushny crystallized the idea in regard to kidney physiology into the so-called modern theory of urine formation, he gave great impetus to the better understanding of all renal physiology. Richards and his co-workers with the capillary pipet have been able to supply existing theories in regard to urine formation with the foundation of experimental proof, which alone seemed lacking in Cushny's summation, that the modern theory indicated some form of filtration in the glomerulus with reabsorption in the tubules. The modern theory was the best result of reasoning from indirect evidence then at hand. The work coming from the laboratory of Richards 1 confirms the theory of fil III IV tration through the glomeruli and reabsorption in the tubules, and as a result the kidney must be looked on as an organ made up of a large num