This work represents an attempt to confirm reported observations of a juxtamedullary by-pass in the kidneys of animals subjected to various physiologic procedures and to shock. Rabbits injected with epinephrine, pitressin, renin and hypertensin, made hypotensive by bleeding and inhalation of amyl nitrite, and after stimulation of one sciatic nerve, were injected with india ink. The kidneys were removed and studied for the paths of blood flow. No evidence of a by-pass mechanism through the juxtamedullary glomeruli was found.