the mucous membrane known as the verumontanum; this acts as a valve that closes the entrance into the bladder and so serves to prevent return flow of the semen during ejaculation. On each side of the verumontanum the floor of the urethra is slightly depressed and perforated by numerous foramina, which are the ducts of the prostate gland; these discharge their viscid secretion into the urethra at this point. Just anterior to the verumontanum is the orifice of a blind pouch, the sinus pocularis, on whose edges are the slit-like openings of the common seminal or ejaculatory ducts. Into this pouch, as it extends backward for about half an inch, numerous tiny glands open. It is lined by columnar epithelium, and discharges its contents into the urethra. When this pocket is involved in inflammatory disease of the urethra, the condition does not respond readily to treatment on account of this anatomic structure. The walls of the prostatic urethra are made up of the firm tissue of the prostate gland, but at the point where the urethra unites with the bladder there is a welldeveloped circular band of smooth muscle-the so-called "cut off muscle."

The membranous urethra is that portion situated between the prostate gland and the bulb of the corpus spongiosum. It is about three-fourths of an inch long, and its anterior part is covered by the bulb of the corpus spongiosum; it is the narrowest portion of the urethra and is lined by stratified columnar epithelium. Its wall is made up of a vascular erectile areolar connective tissue, and of encircling fibers of smooth muscle that are continuous with those fibers that make up the muscular walls of the bladder. These are further augmented by the compressor urethræ muscle, which externally surrounds the membranous portion of the urethra. Into the anterior portion of the membranous urethra enter the ducts of Cowper's glands. These are two racemose glands, situated on each side of the membranous urethra, just back of the bulb. They are lined by clear columnar epithelial cells, and their basement membrane is made up of smooth muscle and areolar connective tissue. They secrete a clear viscid substance which is discharged into the membranous urethra.

The penile or spongy portion of the urethra is entirely inclosed by the erectile tissue of the corpus spongiosum; it is the longest

portion of the canal. In cross-section it is seen as a transverse slit running up to the glans, where it dilates into a spindle-shaped

chamber called the fossa navicularis. This opens on the

surface of the glans by a

Fig. 148.-Longitudinal section through the urethra, showing the large lacunae of Morgagni and the small glands of Littré (after H. Frantz).

vertical slit, the meatus urinarius, which is normally the narrowest part of the entire urethral canal. The penile portion of the urethra is lined by simple columnar epithelium up to the fossa navicularis; there the lining consists of stratified squamous epithelium, which is a continuation of that of the surface of the glans. Numerous small tubular glands whose ducts open out into the epithelial surface are found throughout the entire course of the penile urethra-these are the glands of Littré and the lacunae of Morgagni. They secrete a substance that keeps the mucosa of this portion of the urethra moist. The walls of the penile portion of the urethra

contain no muscle tissue, but

are made up of the epithelium and of a continuation of the con

nective tissue of the corpus spongiosum.

CHAPTER XXII

DISEASES OF THE MALE URETHRA

URETHRITIS

Pathology. Urethritis may, for descriptive purposes, be divided into two forms-the acute and the chronic; this division is capable of further subdivision, and of these the catarrhal and the purulent forms are most important. The condition is most frequently due to infection by the gonococcus, and hence it is the gonorrheal form with which we are chiefly concerned. In the clinical consideration of this disease the term urethritis is used somewhat generally to describe various forms of inflammation of the urethral canal, the term being applied to both those cases in which the gonococcus can and those in which it cannot be demonstrated.

Acute catarrhal urethritis results, as a rule, from the irritation set up by chemic substances excreted in the urine. The changes produced by this condition consist of a hyperemia of the bloodvessels of the mucosa, usually with more or less desquamation of the urethral epithelium, and a greater or less degree of leukocytic exudation and infiltration. When the condition is due to bacterial activity, it is usually succeeded by the development of acute purulent urethritis, under which heading these more important changes will be discussed. Owing to the stimulation of the irritant that produced the inflammation hypersecretion of mucus from the urethral glands takes place, giving to the exudate a char acteristic glairy and mucoid character. When infection follows catarrhal urethritis, particularly when such organisms as members of the proteus or colon group are present, chronic inflammation may follow.

Chronic catarrhal urethritis may occur as a sequel to prolonged acute catarrhal urethritis, but, as a rule, it more frequently follows suppurative and particularly gonorrheal urethritis. In these cases it is usually associated with stricture and with chronic.

inflammation of the mucus-secreting glands. These changes will be discussed at greater length under the sequels of purulent urethritis.

Acute Purulent Urethritis. Acute purulent urethritis may develop as the result of infection of the urethra by any virulent organism, or it may follow the application of an irritant to the urethra for medicinal purposes or the voiding of irritating substances in the urine. The gonococcus is by far the most frequent cause of urethritis, however, as seen by the practitioner. In the discussion of the pathology of urethritis, therefore, the aim will be to adhere to the changes that occur in this most frequent specific type of the disease, it being understood that the anatomic changes that take place in all the infectious forms are practically alike, varying in intensity according to the virulence of the infecting organisms.

Bacteriology. For a proper understanding of the changes that take place in gonorrheal urethritis it is necessary first to consider briefly the biologic characteristics of the gonococcus, for it is by certain of these qualities that the virulence of the disease and its treatment are considerably modified. Perhaps the most important of the biologic characteristics of the gonococcus is its almost strictly parasitic nature, as a result of which the organism cannot live for any considerable length of time except in living animal tissues or in carefully prepared artificial media that closely simulate them. As a further result of this parasitic character, which is further confined to man and the higher apes, gonorrhea is transmitted almost always directly from subject to subject. The organism soon dies when out of the body even when present in moist discharges on infected clothing, so that cases of secondary infection by this means are probably rare. Nevertheless this mode of infection may be sometimes held responsible for the epidemics of gonorrhea seen in children's hospitals. A further characteristic of the organism is its predilection for the mucous and serous surfaces, although hemic infection, as in gonorrheal endocarditis or septicemia, occasionally takes place. No toxins or antitoxic bodies are formed by the gonococcus; and immunity, either natural or acquired, in man is a most unusual condition. This statement must, however, be somewhat modified by the fact

that, under certain circumstances, prolonged exposure to a definite strain or culture of the organism confers a degree of resistance toward it, as is well shown in certain cases of gleet. This peculiarity is noticeable in cases in which, infection having taken place, continued exposure does not result in the breaking out of the infection in one or the other, although either subject would be capable of transmitting it to a third person; if, however, a fresh infection is introduced, active acute inflammatory changes develop. A predisposition to gonorrheal infection undoubtedly exists in many cases, but, in most instances, this is a direct result of conditions facilitating primary inoculation, such as, for example, abrasion or fissure of the exposed epithelial surfaces; simple inflammatory conditions induced by a highly acid urine or by the excretion of alcohol and other chemic irritants.

Mode of Infection. Under normal conditions the epithelium of the fossa navicularis, so capable of obviating bacterial infection, does not permit infection with the gonococcus to take place in this portion of the urethra. If, however, from any cause this surface is eroded or fissured, infection quickly follows. Close clinical observation apparently demonstrates that in many cases the gonococcus may remain in the fossa navicularis for a considerable period of time, and may even reproduce in this portion of the tract, without exciting marked inflammatory reaction. If, however, the organism gains access to the pendulous portion of the urethra, either by direct extension from the fossa navicularis or by being drawn backward by the aspiratory action said to follow relaxation of the bladder or of the extrusor muscle, acute inflammatory reaction almost immediately takes place. These facts have been amply proved by the experimental inoculations of Finger, who showed that gonococci will not penetrate the healthy squamous epithelium of the fossa navicularis under normal conditions, although infection quickly follows the implantation of infectious material on the columnar epithelium of the pendulous portion.

Pathologic Anatomy.-Finger found that three days after infection the mucous membrane was covered with a copious purulent secretion and that the epithelial layer was extensively infiltrated with pus-cells, which, on examination, showed that