The instruments were devised by me to collect the total output of urine from each kidney during an examination to test the capacity for work of each.
The catheters heretofore employed for this purpose have not been satisfactory. Those with bulbous enlargements at the ureteral end do not always succeed in entering the canal and they do not always completely plug it even when they do enter. Those having a small inflatable rubber balloon at the ureteral end which can be inflated after the catheter is in position are open to the objection that the rubber soon deteriorates.
The commonest method has been to pass, with a cystoscope, two No. 8 French catheters, one on each side, and to trust that there will be no leakage alongside the instrument. Leakage is detected by means of a catheter laid in the bladder. Larger double catheterizing cystoscopes which might take larger catheters