An instrument for viewing the interior of the URINARY BLADDER. It consists of a narrow tube carrying a small electric lamp at its end; a small mirror set obliquely opposite an opening near the end of the tube; and a telescope which is passed down the tube and by which the reflection of the brightly illuminated bladder wall in the mirror is examined. It is of great value in the diagnosis of conditions like ulcers and small tumours of the bladder.

Fine CATHETERS can be passed along the cystoscope, inserted into each ureter and pushed up to the kidney, so that the urine from each kidney may be obtained and examined separately in order to diagnose which of these organs is diseased.