Modern methods of clearly outlining the ureter and renal pelvis with opaque material in the roentgenogram and additional studies of the so-called emptying time of the upper urinary tract have furnished definite objective diagnostic data of great value.
It might seem that, with these procedures at one's command, sufficiently accurate data could be obtained to decide whether or not, in a carefully studied patient, abnormal renal mobility actually resulted in distressing or injurious sequelae.
However, the recognition of obstructive processes in and about the ureteral lumen has resulted in such controversy as to the true etiology of upper urinary tract obstruction that the subject of movable kidney cannot be considered apart from such lesions as are tabulated under the headings of ureteral stricture, ureteral kinks, angulation of the ureter, renal torsion and early hydronephrosis. Furthermore, the interpretation of ureteropyelograms by the more experienced observers varies so greatly that when the