Fig. 9, Plate 58, represents the form of an old callous stricture half an inch long, situated midway between the bulb and the meatus. This is perhaps the most common site in which a stricture of this kind is found to exist. In some instances of old neglected cases the corpus spongiosum appears converted into a thick gristly cartilaginous mass, several inches in extent, the passage here being very much contracted, and chiefly so at the middle of the stricture. When it becomes impossible to dilate or pass the canal of such a stricture by the ordinary means, it is recommended to divide the part by the lancetted stilette. (Stafford.) Division of the stricture, by any means, is no doubt the readiest and most effectual measure that can be adopted, provided we know clearly that the cutting instrument engages fairly the part to be divided. But this is a knowledge less likely to be attained if the stricture be situated behind than in front of the triangular ligament. [Illustration] Plate 58.--Figure 9. Fig. 10, Plate 58, exhibits a lateral view of the muscular parts which surround the membranous portion of the urethra and the prostate; a, the membranous urethra embraced by the compressor urethrae muscle; b, the levator prostatae muscle; c, the prostate; d, the anterior ligament of the bladder. [Illustration] Plate 58.--Figure 10. Fig. 11, Plate 58.--A posterior view of the parts seen in Fig. 10; a, the urethra divided in front of the prostate; b b, the levator prostatae muscle; c c, the compressor urethrae; d d, parts of the obturator muscles; e e, the anterior fibres of the levator ani muscle; f g, the triangular ligament enclosing between its layers the artery of the bulb, Cowper's glands, the membranous urethra, and the muscular parts surrounding this portion of the canal. The fact that the flow of urine through the urethra happens occasionally to be suddenly arrested, and this circumstance contrasted with the opposite fact that the organic stricture is of slow formation, originated the idea that the former occurrence arose from a spasmodic muscular contraction. By many this spasm was supposed to be due to the urethra being itself muscular. By others, it was demonstrated as being dependent upon the muscles which surround the membranous part of the urethra, and which act upon this part and constrict it. From my own observations I have formed the settled opinion that the urethra itself is not muscular. And though, on the one hand, I believe that this canal, per se, never causes by active contraction the spasmodic form of stricture, I am far from supposing, on the other, that all sudden arrests to the passage of urine through the urethra are solely attributable to spasm of the muscles which embrace this canal. [Illustration] Plate 58.--Figure 11. COMMENTARY ON PLATES 59 & 60. THE VARIOUS FORMS AND POSITIONS OF STRICTURES AND OTHER OBSTRUCTIONS OF THE URETHRA.--FALSE PASSAGES.--ENLARGEMENTS AND DEFORMITIES OF THE PROSTATE.