_Case 2._--A man, aged fifty, was obliged to exert a strong pressure in order to empty the bladder. The flow of urine often stopped. He himself introduced a catheter, and on withdrawing it a piece of villous tissue was found. On Dec. 10, 1886, I saw, on cystoscopical examination, directly and immediately over the internal orifice of the urethra, a villous swelling hanging from the anterior wall of the bladder. (See Fig. 2.) On Jan. 15, 1887, extirpation of the tumor by means of the high section was performed by Professor v. Bergmann. The size of the tumor (which was as large as a pigeon's egg) and its position corresponded exactly to the endoscopic picture. The patient recovered. [Illustration: FIG. 3.] _Case 3._--A patient under the care of Professor Madelung, aged fifty-five, suffered from attacks of hæmaturia. Examination by sound and rectal palpation had given me negative results. On Feb. 20, 1887, cystoscopical examination was made. On the left side of the trigone a tumor with a broad base was seen, which resembled somewhat a strawberry in size and form. (See Fig. 3.) On March 1, Professor Madelung undertook the extirpation of the tumor. The appearance corresponded exactly to the cystoscopic picture. The patient recovered. [Illustration: FIG. 4.] _Case 4._--This was a patient on whom Dr. Israel had performed the high section a long time before, on account of a bladder tumor. The extent was so great that only its most prominent part could be removed. The microscopical examination proved the diagnosis of cancer. Quick healing took place. The patient became free from pain, and the urine became clear. In order to see what had become of the remaining part, the cystoscopical examination was undertaken on April 3. It was easy to see that the right lateral wall was covered to an extent of from three to four centimeters with thick masses of verrucous and fungiform excrescences. (See Fig. 4.) [We omit the description of the additional cases.]