The mode of infection of the pelvis of the kidney has been and is still a moot question. There is hardly an article on pyelitis that does not include this topic, and yet the available facts can readily be used to prove the mode of infection to be either ascending or hematogenous, depending on the inclination of the authors. Undoubtedly, there are hematogenous infections of the kidney with the staphylococcus and the streptococcus which produce discrete abscesses in the cortex of the kidney and secondary pyelitis. Whether the colon bacillus ever produces renal abscesses in the cortex of the kidney of human beings in this manner has not been definitely determined. That infection of the kidney by the colon bacillus, secondary to some stasis in the urinary tract, is common has been proved, although it is still disputed whether the colon bacillus passes to the kidney by way of the