Clinical experience has established the futility of partial nephrectomy as a surgical measure in cases in which the lesion of the kidney is tuberculous. The purpose of this communication is to contribute further pathologic evidence as to the paths of extension of tuberculosis within the kidney, in justification of operations now employed, rather than to discuss what is already established as a sound surgical procedure.
The observations here recorded were made on a group of twentyone kidneys, obtained at operation, which showed macroscopically a single small lesion at some point in the renal substance with an attendant tuberculous pyelitis. In some instances, the cortex was almost, if not entirely, free from gross lesions, yet in most instances there were a few small cortical tubercles to be seen overlying the gross lesion of the interior of the kidney and connected with it by lines of tuberculous infiltration. There was in each